S50C Steel Plate Supplier | Mold Bases, Carbon Steel, Custom Thickness

S50C steel plate supply supports thickness 10–300mm customization, hardness about HB170–220, applicable to mold base plate processing.

Regular process: material selection→sawing→rough milling→quenching and tempering treatment→fine grinding, delivery time 3–7 days, dimensional tolerance ±0.05mm, ensuring stability and wear resistance.

Mold Bases

Mechanical Tasks & Parameters

S50C medium carbon steel plate internal carbon content distribution is between 0.47% to 0.53%, this determines its thermal stability on injection molding production lines.

Injection molding machine mold closing instant will produce 140MPa or more cavity pressure. S50C mold plate must possess the ability to resist this extrusion, its yield strength reaches 355MPa, able to support 2000-ton class clamping load. If steel plate strength is insufficient, after 500,000 opening and closing cycles, mold plate center will produce more than 0.015mm elastic deformation, directly leading to plastic finished products appearing overflow flash.

· Parallelism error between mold plate four corners controlled within 0.025mm.

· Guide pillar installation hole verticality deviation is limited to 0.015mm.

· Steel plate surface Brinell hardness difference in different areas must not exceed 15HB.

· Load-bearing surface flatness error requirement lower than 0.015mm.

· Internal cooling water channel distance from mold plate surface safety wall thickness at least leave 12mm.

CNC machining center for this steel performing rough milling, spindle speed usually controlled at 1000rpm, matching 50mm diameter fly cutter. Per tooth feed rate set at about 0.2mm, can let cutting produced heat along with blue-purple chips quickly discharge. This processing parameter ensures tool when cutting S50C wear rate remains at low level, single tool setting can continuously process 3 pieces or more standard plates.

Cooling water channel layout determines molding efficiency. Diameter 10mm deep hole water channel with 40mm spacing parallel distribution, can mold surface temperature difference control within 5 degrees Celsius. High efficiency heat transfer performance lets injection molding cycle shorten 4 seconds, in annual output 1 million pieces production task, this corresponds to production efficiency 15% growth and 150 man-hours saving.

· Steel plate material density is 7.85g/cm³.

· Tensile strength measured value usually around 600MPa.

· Elastic modulus maintained at 210GPa.

· After fine grinding surface roughness reaches Ra 0.8 standard.

· At factory time anti-rust grease layer thickness controlled at 15 microns.

Purchasing 132mm custom thickness steel plate, compared to 150mm standard specification, can directly reduce 18mm heavy milling amount. For a piece 1000mm square mold plate, less produce 141 kg steel slag waste. This size customization not only saves raw material cost, but also for subsequent CNC processes saves 5 hours processing time, reduces about 80kWh electric energy loss.

Guide pillar and guide bush between fit clearance maintained at 0.02mm, lubricating oil film thickness controlled at 4 microns. Under 2000-ton clamping force repeated impact, S50C plate can effectively absorb mechanical vibration. Side force reaching 40kN, because steel internal structure uniform, guiding system will not occur due to metal fatigue caused micron-level displacement offset.

High grade S50C through vacuum degassing process, sulfur impurity content reduced to below 0.02%. This purity in deep hole drilling processing performance obvious, can avoid drill bit meeting internal hard points and cracking. In up to 1000mm water channel drilling, hole position offset lower than 0.05mm, ensuring cooling channel will not with ejector pin hole or bolt hole occur interference dislocation.

Assembling mold base, M20 high strength bolt pre-tightening torque set at 280Nm. Adopting cross method in three times tightening, ensuring fixed mold base plate and moving mold base plate between fit flatness reaches 0.005mm. If torque uneven, under 150MPa injection back pressure, mold plate edge will appear 0.03mm open gap, leading to product wall thickness appearing visible to the naked eye asymmetry.

Bottom cushion block height error must compressed within 0.008mm, this relates to whole set mold on injection molding machine pressure plate force uniformity degree. If bottom support point exists height difference, injection molding machine clamping time produced huge compressive stress will make mold plate occur 0.02mm depression deformation.

During warehouse storage period, environmental humidity needs controlled below 45%. S50C steel in 70% humidity environment, exposed surface will in 36 hours appear brown oxidation spots. Using 20 micron thickness plastic film combined with anti-rust paper performing vacuum packaging, can let precision processed mold base surface in 12 months not produce any rust, maintaining 0.01mm fit precision.

Every executing 100,000 injection cycles, need for mold base perform five key points thickness measurement, detecting whether exists permanent mechanical compression. Once found plate thickness change exceeding 0.01mm, then explains material already approaches fatigue limit.

Before factory quality inspection using CMM checking 30 items geometric data. Gate bushing center position offset strictly prohibited exceeding 0.01mm. This precision maintenance, ensures 220 degrees Celsius molten plastic can with constant pressure enter mold. Because runner resistance reduced to minimum, injection molding process energy loss also correspondingly reduced about 8% around.

S50C Steel 3 Advantages

S50C steel internal contains 0.5% medium proportion carbon element, giving it in cutting processing excellent chip breaking ability. In workshop actual measurement, using diameter 63mm R6 ball end mill for S50C performing cavity roughing, spindle speed maintained between 1100rpm to 1300rpm. At this speed, insert cutting edge surface temperature remains below 550 degrees Celsius, preventing carbide tool occurring premature annealing failure.

Compared to higher hardness P20 or 718 mold steel, S50C for CNC machine spindle load reduced about 25% to 30%. During performing 1000mm depth aspect ratio drilling operation, S50C cutting resistance performance stable, drill bit per minute feed rate can reach 150mm or more. Material internal fine pearlite structure ensures cutting surface will not appear obvious tearing marks, after fine milling surface roughness can easily reach Ra 0.6 to Ra 0.8 standard.

· Tool life than processing P20 steel extended more than 40%.

· Spindle speed stable at 1200rpm, feed rate maintained at 0.2mm per tooth.

· Cutting fluid consumption under same processing volume reduced about 15%.

· Roughing stage chip removal efficiency than alloy tool steel higher 20%.

· Single mold base plate CNC processing man-hours average shortened 4.5 hours.

· Machine spindle bearing vibration frequency remains below safety threshold 5g.

Material internal stress relief annealing process residual stress controlled below 20MPa. This for 1.5 meters or more large mold base essential, preventing after large area milling off 30% volume, plate occurs more than 0.05mm deflection deformation. S50C thermal expansion coefficient in room temperature to 200 degrees Celsius range is 12 x 10^-6 per degree Celsius, ensuring injection process upper and lower molds in thermal balance state precision positioning, mold closing gap fluctuation intensity lower than 0.005mm.

S50C elastic modulus reaches 210GPa, under 150MPa cavity instantaneous back pressure impact, mold plate center elastic depression amount controlled within 15 microns. Because material internal through vacuum degassing process removed excess hydrogen, oxygen content, sulfur content compressed to below 0.02%, greatly reducing under high frequency vibration environment producing fatigue crack risk.

· Mold closing surface after 500,000 impacts flatness error less than 0.02mm.

· Guide pillar positioning hole in continuous operation roundness out-of-tolerance controlled at 0.008mm.

· After heat expansion diagonal size deviation remains within 0.03mm.

· Material internal hardness point range distribution in 5HB to 10HB small range.

· Thickness 150mm plate after processing warpage lower than 0.1mm.

· Cooling water channel wall surface under 1.0MPa water pressure anti-erosion life exceeds 5 years.

If mold design requirement is 132mm thick plate, market common 150mm standard specification will produce 18mm metal waste. Taking a 1200mm long, 800mm wide mold plate for example, this 18mm excess thickness equivalent to about 135 kg steel weight, according to current market price calculation, each mold plate raw material purchase expenditure extra increased about 15% to 20%.

Excess 18mm thickness on CNC machining center at least needs performing 6 times rough milling cycles. According to per hour 200 yuan machine rental cost and per hour 15kWh electricity consumption calculation, single plate processing cost increased about 1200 yuan. Suppliers providing custom thickness control tolerance between +0.2mm to +0.5mm, making mold factories after getting plate can directly enter semi-finish milling process, overall delivery cycle shortened 2 working days.

On global range, HASCO, DME, LKM etc. mainstream mold base systems all take S50C as benchmark material. Whether in Southeast Asia OEM factories or Europe assembly lines, engineers all can obtain consistent material mechanical performance parameters. Spare parts replaceability extremely strong, even if in production site occurs guiding system damage, also can in 24 hours obtain performance benchmarked S50C replacement components.

· Global inventory coverage rate in mold base materials accounts for more than 65%.

· Matching guide pillars, guide bushes standardization tolerance uniformly executes g6/h6 level.

· After surface nitriding treatment hardness can increase to HV500 to HV600.

· Anti-rust paint after surface spraying adhesion grade reaches level 1.

· Material composition batch consistency deviation controlled within 3%.

· Scrapped mold base steel recovery value remains at original price 25% around.

Although in mold base applications mostly delivered in normalized state, but targeting need local wear-resistant slider or lifter parts, through induction hardening can surface hardness increase to 45HRC or more, while core still maintains 355MPa yield toughness.

High purity S50C steel plate in deep hole processing shows extremely high safety. In depth exceeding 800mm gun drilling process, because material internal has no non-metallic inclusions larger than 0.02mm, drill head carbide insert will not encounter sudden chipping. Cooling water channel and ejector pin hole between minimum safety distance can shorten to 8mm, for mold internal complex mechanism arrangement vacate key space.

In 40% humidity air-conditioned machine room, exposed steel scale growth speed lower than 0.001mm/month. After fine processing mold base in inventory stored half year, its fit precision still can maintain within 0.01mm error range. Every 100 kg steel anti-rust oil coating amount only needs 50 grams, this not only reduces chemical expenditure, also reduces later mold cleaning time solvent usage.

Carbon Steel

Carbon Steel Classification

Iron element and carbon element atom ratio determines steel basic mechanical performance. When carbon content lower than 0.02%, material in industry is classified as industrial pure iron, texture extremely soft and magnetic permeability high. Once carbon content enters 0.02% to 2.11% between, material shows significant strength increment, this is exactly Carbon Steel physical boundary.

Low Carbon Steel typical representative such as AISI 1018 or S20C, its carbon content usually limited between 0.15% to 0.25%. This type steel tensile strength maintained at 370 MPa to 490 MPa, elongation exceeds 25%. This high ductility makes it in 1000-ton class press under cold stamping process, plate edge not easy to produce tear cracks.

Medium Carbon Steel such as S50C or AISI 1050, carbon content increased to 0.47% to 0.53% level. Through 850°C normalizing treatment, grain size can reach grade 6 or above, Brinell hardness stable at 170 HB to 220 HB. This hardness level ensures in large injection mold bases (Mold Bases) bearing 500 tons clamping force, support plate surface will not occur permanent plastic subsidence.

High Carbon Steel such as T10 or SK5, carbon content breaks through 0.60% even reaching 1.0%. This type steel after quenching Vickers hardness (HV) can exceed 700, but impact toughness will drop to 5 J/cm² below. Due to its extremely high internal stress, in manufacturing thickness exceeding 50mm large plates, if not performing 650°C high temperature stress relief annealing, material in cutting process will occur spontaneous bursting.

Manganese element in S50C proportion usually set between 0.60% to 0.90%. Manganese role lies in improving steel hardenability, making thickness 200mm steel plate in oil cooling quenching, hardness layer can penetrate to surface below 15mm. If manganese content lower than 0.3%, thick plate center position structure will coarsen, leading to mold base in deep hole drilling water channel appearing serious drill deviation phenomenon.

Silicon content controlled in 0.15% to 0.35% range. Silicon in steelmaking furnace as deoxidizer, can discharge molten steel internal free oxygen, reducing finished steel plate internal micro-pores. For thickness 150mm or more custom thickness plates, through 2.5 MHz frequency ultrasonic testing (UT), testing grade needs to reach SEP 1921 standard C/c grade, this requires internal single defect diameter must not exceed 3mm.

Sulfur (S) and Phosphorus (P) are harmful impurities in carbon steel, their content must suppressed below 0.035%. Phosphorus content exceeding standard will lead to "cold shortness", namely in 0°C below environment, steel when impacted will like glass same break. Sulfur content too high then will form manganese sulfide inclusions, when performing Ra 0.8 grade mirror polishing processing, these inclusions will fall off and form visible to the naked eye spot pits.

Heat treatment process determines S50C steel plate final service performance. Heating steel to 830°C austenitizing temperature, maintaining per 25mm thickness 30 minutes holding time, followed by performing forced air cooling or water quenching. After 600°C tempering, S50C yield strength can from 390 MPa increase to 500 MPa or more, at this time material internal sorbite structure has excellent strength-toughness coordination ratio.

In CNC machine cutting S50C, tool linear speed generally takes 180 meters/minute. Using diameter 50mm fly cutter for face milling, per tooth feed rate set at 0.2mm, single cut depth can reach 3mm. Produced iron chips should show dark blue spiral shape, this represents 80% of cutting heat already with iron chips taken away, ensuring steel plate after processing thermal deformation displacement amount less than 0.02mm.

Custom Thickness processing precision is indicator to measure supplier level. Adopting double-side milling machine processed S50C plates, thickness tolerance should limited between +0.1mm to +0.2mm. If requiring more precision, grinder processing can compress flatness tolerance to 0.01mm/500mm range, this for needing precision alignment multi-cavity injection mold base plate essential.

In injection mold production, mold temperature usually maintained at 60°C to 120°C. Through calculating this expansion coefficient, engineers can precisely reserve mold cavity shrinkage rate. Its thermal conductivity is 45 W/(m·K), than many high alloy tool steels higher 20%, effectively shortening plastic product cooling molding cycle.

Thickness exceeding 100mm hot rolled plates in cooling process will produce huge residual stress. Supplier needs before delivery performing stress relief annealing, namely heating steel plate to 550°C holding 5 hours then cooling with furnace. Non-stress relieved plates after through laser cutting or wire cutting slotting, plate body will produce 2mm or more deflection deformation, directly leading to subsequent precision grinding unable compensate dimensional deviation.

Laser cutting S50C time, 20mm thickness below plates can adopt 12kW or more fiber laser. Cutting gas using nitrogen or oxygen, pressure maintained at 0.5 MPa to 1.2 MPa. Oxygen cutting will at cut edge form a layer about 0.5mm thick black oxide scale, its composition mainly ferroferric oxide.

Chemical Composition

S50C steel plate carbon content precisely set between 0.47% to 0.53%. Carbon atom diameter about 0.154 nanometers, it forcibly squeezes into iron atom lattice gaps. This microscopic distortion fixes material basic tensile strength at 630 MPa or above. If carbon content deviation exceeds 0.05%, mold base after heat treatment surface hardness will appear 3 to 5 HRC discrete fluctuation.

Manganese element in molten pool proportion usually controlled at 0.60% to 0.90%. Manganese can with sulfur combine form manganese sulfide (MnS), this compound melting point as high as 1610°C. In 1200°C hot rolling process, manganese sulfide shows plastic state following rolling direction extending. Lacking sufficient manganese will lead to low melting point eutectic production, making thick steel plate in hot processing stage from internal occur hot shortness cracking.

Silicon in S50C smelting plays key deoxidation role, content remains in 0.15% to 0.35% range. In 1600°C molten steel, silicon quickly seizes dissolved oxygen and produces silicon dioxide slag. This deoxidation reaction blocked steel ingot solidification time producing diameter 0.1mm or more subcutaneous bubbles. Through this treatment, 250mm thickness custom plates under ultrasonic testing can reach per square meter defects less than 2 pieces level.

· Phosphorus Content: limited below 0.030%, preventing 0°C below environment cold shortness fracture.

· Sulfur Content: locked within 0.035%, ensuring mold polishing after not appearing strip-like sand holes.

· Chromium Residual: usually below 0.20%, avoiding machining time meeting unpredictable abnormal hard points.

· Nickel Residual: maintained below 0.20%, while ensuring strength controlling material purchase cost.

· Copper Content: upper limit set at 0.25%, preventing steel plate surface in high temperature environment producing network cracks.

Phosphorus in ferrite solubility extremely low, easy to produce segregation at grain boundaries. When phosphorus proportion breaks through 0.04%, steel when bearing impact load, crack expansion speed will increase 20% or more.

Sulfur element although regarded as impurity, but in S50C cutting performance plays lubrication role. Uniformly distributed manganese sulfide particles can play chip breaking role, reducing contact area between tool and steel surface. In CNC linear speed 200 m/min condition, sulfur content at 0.02% around plates, its tool durability than extremely low sulfur (<0.005%) steel higher about 15%.

Residual elements Chromium (Cr) and Nickel (Ni) mostly come from scrap steel recycling process. Although these elements do not belong to S50C standard added items, but 0.1% around trace existence can slightly increase material hardenability. For thickness exceeding 150mm large size mold base, trace chromium element helps in water quenching process, making hardened layer depth extra towards center penetrate 2mm to 3mm.

· Carbon Equivalent (Ceq): S50C calculated value about 0.62% to 0.75% between.

· Preheating Temperature: before welding operation must increase temperature to 150°C, preventing hydrogen-induced cracks production.

· Gas Content: molten steel oxygen (O) content needs below 20ppm, nitrogen (N) below 70ppm.

· Structure Composition: room temperature delivery state usually lamellar spacing 0.2 micron pearlite.

· Purity: non-metallic inclusion rating in A, B, C, D classes all need less than 1.5 grade.

Aluminum (Al) often as refining grain element is trace added, content usually between 0.015% to 0.040%. Aluminum with nitrogen combining producing aluminum nitride (AlN) particles distributed at grain boundaries, like rivets same pinning austenite grain boundaries. In 850°C normalizing heating process, these particles block grains quickly coarsening, making finally obtained grain size grade stable at grade 7 or 8.

Steel plate internal oxygen, hydrogen, nitrogen etc. gas element content directly affects material density. Hydrogen atoms in steel internal aggregating produced pressure can reach several hundred MPa, this will lead to thick plates appearing visible to naked eye invisible "white spots" defects. Professional suppliers in producing 100mm or more thick plates, will adopt vacuum degassing (VD/VOD) process, lowering hydrogen content to 2ppm below.

Custom thickness S50C steel plates through adjusting manganese carbon ratio (Mn/C) to optimize processing stability. When ratio remains between 1.5 to 2.0, steel strength and plasticity reach best balance. In deep hole drilling processing diameter 20mm, depth 1000mm cooling water channel, this composition ratio can reduce drill bit deviating from axis probability, deviation amount usually can controlled within per meter 1.5mm.

· Thermal Conductivity: 45 W/(m·K), in carbon steel belongs to high efficiency heat conduction level.

· Cutting Resistance: unit cutting force about 2100 N/mm², for machine spindle rigidity has certain requirement.

· Magnetic Permeability: saturation magnetic induction intensity 2.0T, adapts to various electromagnetic chuck fixtures.

In flame cutting thickness 300mm S50C steel plate, edge 5mm area chemical composition will because local high temperature occur change. Carbon element might at cut surface occur slight decarburization, leading to that place hardness drop to 150 HB around. To correct this deviation, fine processing stage must reserve 8mm allowance, through mechanical cutting stripping this layer heat affected zone, exposing internal chemical composition uniform basic material.

Quality Inspection Specifications

S50C steel plate thickness detection uses scale value 0.01mm digital micrometer or ultrasonic thickness gauge, measurement frequency set at 5MHz. For 100mm specification custom thickness plates, measured thickness usually maintained at 100.15mm around, extra 0.15mm left for subsequent fine processing allowance. In large size 1500mm x 2000mm plate surface, adopting diagonal 5 points sampling method, each point deviation value compressed within 0.08mm.

Brinell hardness (HB) test uses 10mm diameter carbide ball indenter, applying 3000kg test force and maintaining 15 seconds loading time. S50C in delivery state hardness value usually distributed between 170 HB to 210 HB . If measured data drops below 160 HB, represents material in 850°C normalizing stage cooling rate insufficient, internal pearlite lamellae too thick, will lead to subsequent milling processing produce serious tool sticking.

Ultrasonic testing (UT) executes SEP 1921 level C/c grade standard, detection head sensitivity adjusted to 3mm flat bottom hole. In scanning thickness 200mm steel plate, sound wave return waveform if appearing more than base wave 20% noise, judged internal exists micro shrinkage holes.

· Spectrometer in 10 seconds excites 3 times sparks, measuring carbon, manganese, silicon, sulfur, phosphorus content average values.

· Each plate side laser inkjet 12 digits heat number, one-to-one corresponding with EN 10204 3.1 material certificate.

· Sulfur, phosphorus impurities total proportion limited below 0.05%, preventing polishing surface layer time appearing 0.1mm level sand holes.

· Plate flatness tolerance executes per meter less than 0.05mm standard, reducing 30% rough processing man-hours.

· 100mm or more thick plate needs performing 550°C stress relief annealing, residual stress value detection needs below 30 MPa.

After double-side fine milling S50C steel plate, surface roughness Ra value calibrated at 1.6 microns. Through stylus roughness tester measurement, sampling length set at 0.8mm, continuous scan 5 times. This surface precision matching 2.0 grade flatness, making plate placed on electromagnetic chuck, adsorption force can reach per square centimeter 150N rated value, ensuring high speed milling time not produce displacement.

Material certificate records yield strength Rp0.2 and tensile strength Rm specific values, S50C Rm stable between 630 MPa to 780 MPa. Elongation A recorded value on certificate should more than 14%, this represents steel when bearing pressure possesses certain buffer margin. All detection data must by obtained ISO 17025 certification laboratory seal, data flow possesses whole process traceable legal effect.

Visual inspection covers plate six sides, excluding depth exceeding 0.5mm rolling folds. Side flame cutting left ripple height must less than 1mm, and heat affected zone hardened layer depth controlled within 3mm. Through temperature gun monitoring cutting time edge temperature, if instantaneous exceeds 1000°C and not timely performing cooling compensation, material edge will produce 0.2mm thick martensite brittle layer.

Targeting 150mm or more ultra-thick plates, center area carbon segregation detection through macroetch test completed. Immersing cross section in 50% hydrochloric acid water solution, temperature maintained at 70°C. If center position appears obvious dark black spots, explains carbon element segregation exceeds 1.15, this material in deep hole drilling processing diameter 20mm water channel, drill bit easy to deviate from axis 2mm or more.

· Thickness tolerance controlled at +0.1/-0 mm, avoiding mold base assembly appearing step difference.

· Side verticality with 90 degree square ruler matching feeler gauge detection, tolerance per 100mm less than 0.02mm.

· Steel plate four sides need performing 1.0mm x 45 degrees chamfer treatment, removing 100% of cutting flash.

· Plate markings include steel mill code, grade, specification, heat number, piece number total 5 elements.

· Per ton plate extract 2 samples performing metallographic structure observation, pearlite content needs account for 80% or more.

After 550°C constant temperature 6 hours, through blind hole method measuring surface residual stress. Qualified S50C steel plate after roughing processing, its length and width direction size change amount should less than 0.01%, this for maintaining 0.02mm positioning pin hole position tolerance essential.

Packaging stage anti-corrosion layer thickness needs reach 15 microns. Using dry film thickness gauge on plate surface uniformly take 4 measurement points, if coating oil uneven will lead to ferric oxide in 48 hours produce. Adopting 0.12mm thick vacuum PE film sealing, matching active mineral desiccant, ensuring sea transport process chloride ions unable penetrate to steel plate surface, maintaining material delivery metal original color state.

Measuring 200mm thick plate parallelism, needs placing steel plate on 0 grade marble platform, utilizing scale value 0.001mm lever percentage meter performing sweeping. When percentage meter pointer swing amplitude within 0.03mm range, explains material parallelism reaches precision mold base installation requirement, can reduce injection molding machine moving and fixed mold closing time micron-level wear.

Hardness distribution uniformity detection requires from steel plate edge towards center every 50mm determining one point. S50C in 1.5 meters width range hardness difference should not exceed 15 HB. If edge hardness too high (such as reaching 240 HB), explains rolling cooling water pump pressure uneven, will lead to machine cutting to edge time due to hardness mutation causing carbide insert occur 0.1mm micro-chipping.

Custom Thickness

Cutting Allowance & Cost

A piece 2000mm long, 1000mm wide S50C standard thickness 50mm steel plate, physical weight reaches 785kg. If mold base drawing marks finished thickness 42mm, purchasing regular 50mm plate must through gantry milling machine cut off 8mm excess metal. This layer shaved off steel weighs as much as 125.6kg. According to current medium carbon steel market price and scrap steel recovery price difference conversion, single plate material loss produced fund loss exceeds 650 yuan.

Custom thickness controls raw material at 43.5mm. Reserving 1.5mm processing allowance is for subsequent double-side fine milling leaving flatness correction space. This millimeter-level size control, eliminates machine in large load under performing up to 4.5 hours rough milling operation. Machining workshop 15kW spindle motor in continuous high strength cutting, per hour consumes 12 to 15 degrees electricity, saving roughing stage let each plate can save about 60 degrees industrial electricity.

· S50C medium carbon steel carbon content between 0.47% to 0.53%, hardness distribution in HB 170 to 210.

· Rough cutting selects WNMG080408 carbide inserts, under cut depth 3mm, feed rate 0.25mm/rev, each edge life 80 minutes.

· Milling 8mm thickness needs dividing into 3 times feeding, tool change frequency and wear cost account for 15% or more of processing expenditure.

· Custom thickness plates adopt Gantry milling machine double-side one-time leveling, thickness deviation controlled at plus or minus 0.08mm.

From 50mm milling to 42mm, single side removal amount reaching 4mm, steel plate internal balance will be broken. Plate center will appear upward tension, leading to flatness error from 0.05mm surge to 0.25mm. This warpage deformation in later mold assembly leads to parting surface unable to close, producing overflow flash.

Adopting large CNC band saw machine performing cold cutting, saw blade linear speed maintained at per minute 45 meters to 60 meters. This process ensures cut section heat affected zone depth less than 0.2mm.

1. Steel plate four corners and center point thickness measured value error not exceeding 0.15mm.

2. 50mm or more thick plate through ultrasonic detector performing 100% coverage testing.

3. Surface roughness Ra value stable at 3.2μm to 6.3μm, convenient for fitter marking.

4. Cutting surface verticality allowance controlled at per 100mm thickness less than 1mm.

5. Edge burr removal rate 100%, preventing hoisting in wire rope damaged.

In mold base manufacturing cycle, raw material pre-preparation occupies total construction period 30%. Purchaser getting near finished custom thickness pieces, mold base closing, drilling, installation guide pillar guide bush processes can advance 2 working days start. For precision injection mold projects, 48 hours advanced delivery usually let factory avoid logistics peak and downstream trial mold equipment scheduling conflicts.

S50C silicon content in 0.15% to 0.35%, manganese content in 0.60% to 0.90%, these components determine cutting performance. When thickness specification from 50mm reduced to custom 44mm, heat treatment quenching permeability performance more uniform. Plate center hardness and surface hardness difference by original HB 35 narrow to within HB 15.

· 10mm to 150mm thickness range supports every 1mm grade specification ordering.

· 200mm or more ultra-thick plate adopts constant temperature annealing treatment, holding time per 25mm thickness not less than 1 hour.

· Double-side fine milling equipment worktable surface reaches 2500mm by 4000mm, supports multi-piece simultaneous processing.

· Delivery cycle from standard plate 24 hours response becomes 48 hours custom.

In material warehouse actual operation, each piece custom thickness S50C will inkjet code identification, recording original heat number and measured thickness. This fine management mode replaces rough inventory stacking. Purchaser does not need in factory establish huge stagnant inventory, only need according to production plan before assembly 3 days allocate in place.

Thickness exceeding 80mm S50C custom pieces, before factory experience vibration aging treatment. Through exciter at specific frequency under acting 20 to 30 minutes, eliminating internal 90% or more residual stress. Processed custom thickness steel plate, even if later experiencing high frequency injection impact pressure, its size stability also can maintain at per year 0.02mm level.

Controlling Internal Stress

A piece 1000mm by 2000mm S50C medium carbon steel plate, thickness from 50mm milling to 42mm, metal internal static balance will be broken. S50C yield strength at 355MPa around, hot rolling process cooling uneven produced residual stress lurking in fiber structure. When single side cut amount reaches 4mm, originally by surface layer tensile stress offset internal compressive stress instantaneously released, steel plate will like a banana same produce upward or downward arc.

Ordinary S50C plate at factory hardness distribution in HB 170 to 210, this hardness span originates from carbon content in 0.47% to 0.53% between fluctuation. If directly taking 50mm standard plate entering roughing, tool tip in cut depth 3mm, feed rate 0.3mm state, produced heat will let local temperature soar to 600 degrees Celsius or more. Thermal stress superimposing structure stress, will let a 2-meter long steel plate after unloading magnetic chuck, center position appear 0.3mm or more bounce.

Custom thickness compresses cutting allowance within single side 0.5mm to 1.0mm, this equivalent to stress release scale reduced 85% or more. Thin cutting produced heat extremely few, heat affected zone (HAZ) depth controlled within 0.1mm, metal lattice remains stable. This approach directly bypassed large area stripping metal brought structure imbalance, ensuring mold base in subsequent drilling, slotting processes, position tolerance can stabilize within 0.02mm.

· S50C thermal expansion coefficient about 11.5 x 10^-6, every increase 100 degrees, 1 meter length extends 0.115mm.

· Large amount cutting time, plate surface and center temperature difference exceeding 50 degrees, extremely easy to induce physical size permanent drift.

· Manganese content 0.60% to 0.90% ratio although improved hardenability, but at same time increased thermal stress sensitivity.

· Custom thickness plates before delivery will experience 4 hours 200 degrees low temperature stress relief tempering, ensuring molecular arrangement tends to inert.

In mold base manufacturing, if cushion plate flatness exceeds 0.1mm, injection pressure will distribute unevenly. S50C internal silicon element content in 0.15% to 0.35%, its main role is deoxidation, but too high silicon also increases material brittleness. If through custom thickness reduced machine processing time, then disguised reduced tool to plate surface high frequency vibration impact. This frequency in 2000Hz to 5000Hz between vibration, is hidden danger inducing micro cracks and fatigue stress.

For thickness exceeding 80mm heavy mold base, we will after custom cutting performing 20 to 30 minutes vibration aging (VSR) treatment. Exciter will find plate resonance frequency, at 5000 rpm under, through resonance energy let metal atoms occur microscopic displacement. This operation can offset 90% or more production stress. Processed steel plate, even in south humid, temperature difference large workshop placed 3 months, flatness change amount also not exceeding 0.01mm.

· Sawing linear speed: per minute 40 meters to 55 meters, preventing edge cold work hardening.

· Thickness tolerance: customized plate factory actual measurement, ensuring positive tolerance in 0.2mm to 0.5mm.

· Parallelism indicator: per meter length parallelism error less than 0.05mm.

· Surface hardness gradient: surface and core hardness difference controlled within HB 10.

Flame cutting temperature as high as 1000 degrees or more, will at edge form width reaching 5mm hardened layer, hardness might instantaneously jump to HRC 45 or more. Subsequent processing, milling cutter once meeting this hardened area, will occur chipping or serious chatter marks. Cold cutting process then completely avoided thermal expansion contraction process, letting steel plate from beginning to end maintain original mechanical performance.

In actual production cases, a mold factory uses custom thickness 42.5mm S50C replacing 50mm standard plate. Originally needing 2 days to complete cushion plate processing, shortened to 6 hours. Not only saved 120 or more kg steel waste, more avoided because stress deformation leading to rework maintenance. Machine operator feedback, due to allowance extremely small, spindle load long-term maintained below 30%, tool package service life extended 3 times, each product saved tool fee reaching 40 yuan.

1. Entrance detection: using ultrasonic testing gauge scanning whether internal has structure porosity or inclusions.

2. Geometric review: utilizing large level meter, for custom plate four corners performing horizontal displacement detection.

3. Chemical consistency: ensuring each batch steel plate manganese carbon ratio error within 0.02%.

4. Packaging protection: smearing anti-rust oil and adding anti-collision wooden tray, preventing transport produced physical deformation.

Steel physical inertia irreversible, once in roughing stage because stress led to bending, subsequent even if repeated grinding, material internal still exists "rebound memory". This memory will in mold heating to 60 degrees working temperature again manifest, causing closing precision decrease. Choosing custom thickness, essentially is at source avoided metal structure violent change, letting each piece S50C steel plate can with most peaceful internal state enter machine, this for precision manufacturing than pure price discount more meaningful.

Cutting Process

S50C plate cutting process, CNC band saw cold cutting process is foundation to maintain material original physical performance. For thickness in 20mm to 200mm between custom pieces, saw blade linear speed usually set at per minute 45 meters to 60 meters. Adopting M42 or M51 bi-metal band saw blade, tooth pitch selects 3/4 tooth or 2/3 tooth, ensuring cutting edge in contact metal instant produced heat by circulating cooling liquid quickly taken away, cut edge temperature always controlled below 80 degrees Celsius.

Cold cutting mode avoided metal lattice secondary reorganization, S50C original HB 170 to 210 hardness at cut section not occur jump. By comparison, traditional laser or plasma cutting at edge produced heat affected zone (HAZ) depth often exceeding 3mm. These heat affected zone hardness will because quick heat quick cold and soar to HRC 50 or more, subsequent processing, per minute 200 meters speed carbide milling cutter once cutting into this area, tool tip wear speed will accelerate 5 times.

Custom thickness sawing precision deviation set between positive 0.2mm to positive 0.8mm. This reserve amount covered subsequent double-side milling machine first cut feed depth, machine operator does not need in alignment tool setting link waste more than 15 minutes calibration time.

CNC sawing machine feed pressure stable at 2.5MPa to 3.0MPa, this value can prevent saw blade in thick plate cut-off process produce physical deflection. If cutting a piece 300mm thick large S50C mold base, saw downward deviation if exceeding 1mm, machine processing link needs extra more milling off about 15 kg metal. Through frequency conversion motor adjusting saw blade tension to 30000psi, cut verticality can stabilize within per hundred mm 0.5mm.

· Saw blade life: single M42 saw blade in cold cutting S50C time, cumulative cutting area can reach 8 square meters to 12 square meters.

· Cutting fluid ratio: adopting 1:20 concentration fully synthetic cooling liquid, reducing cutting resistance at same time preventing plate edge oxidation rust.

· Rhythm data: cutting a piece thickness 50mm, width 500mm S50C plate, pure cutting time about 12 minutes, edge burr thickness less than 0.1mm.

· Equipment load-bearing: large sawing machine worktable load-bearing ability reaches 20 tons, supports multi-plate overlapping cutting, single cycle output efficiency increased 40%.

When S50C plate thickness exceeds 250mm, flame cutting process enters application scope. Propane gas pressure controlled at 0.05MPa, oxygen pressure adjusted to 0.5MPa, this air-fuel ratio can produce smoother cut section. To prevent thick plate in thermal cutting produce cracks, before cutting needs steel plate preheating to 200 degrees Celsius, after cutting edge annealing treatment maintains at 550 degrees Celsius, constant temperature holding 3 hours to eliminate thermal stress induced physical deformation.

Each cutting completed custom piece will at side spray heat number identification. Records show, through vibration stress relief processed custom thickness steel plate, in indoor storage 30 days later size shrinkage rate lower than 0.005mm, this for mold parting surface sealing precision provided data base.

Plate at sawing machine clamping pressure remains at 40bar to 60bar, preventing high frequency reciprocating motion induced displacement. Targeting S50C medium carbon steel manganese content 0.60% to 0.90% characteristic, cutting process chip removal groove design width must reach 1.2mm or more. If chips lag in saw seam, will induce secondary friction heat, leading to plate local hardness uneven, then affecting mold base drilling process twist drill centripetal precision.

1. Saw seam width: standardization controlled at 2.0mm to 2.5mm, material utilization compared to traditional process improved 5%.

2. Surface roughness: cold cut surface roughness Ra value in 6.3 to 12.5 microns, no need rough grinding then enter milling machine operation.

3. Size consistency: same batch 50 pieces custom thickness plates, thickness range controlled within 0.3mm.

4. Edge detection: adopting magnetic particle testing random check thermal cut piece edge, ensuring 100% no micro crack extension.

Machining workshop data feedback, using cold cut custom thickness S50C, spindle motor load compared to using flame cutting plate reduced 25%. Due to no edge hardening layer, fine milling time feed rate can from per tooth 0.15mm increase to 0.22mm. Single piece processing man-hours shortened 35 minutes, corresponding electricity and labor cost comprehensive reduction reaches per piece 85 yuan.

Material warehouse equipped infrared thermometer will for each piece out of furnace thermal cut plate perform monitoring. When environment temperature and plate temperature difference exceeds 40 degrees, strictly prohibited direct stacking, must leave 150mm heat dissipation gap.