| Customization: | Available |
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| Type: | Sheet |
| Standard: | AISI |
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4140 round steel ,4140 forging ,4140 steel plate
In terms of material classification, 4140 round steel belongs to alloy structural steel, which has good mechanical properties and machinability, and is widely used. It mainly consists of two types of materials: plate and round rod. Its comprehensive performance is better than 40cr and has been recognized by the industry.
4140 round steel steel belongs to ultra-high strength steel, with high strength and toughness, hardenability is also good, no obvious tempering brittleness, tempering treatment after higher fatigue limit and resistance to multiple shocks, low temperature impact toughness is good. 4140 round steel is suitable for manufacturing large and medium-sized plastic molds requiring certain strength and toughness.
Chemical composition of 4140 round steel
C: 0.38 ~ 0.45%
Si: 0.17 ~ 0.37%
Manganese Mn: 0.60 ~ 0.80%
Sulfur S: Allowable residual content ≤0.035%
P: Allowable residual content ≤0.035%
Cr: 0.90 ~ 1.20%
Nickel Ni: Allowable residual content ≤0.30%
Copper Cu: Allowable residual content ≤0.30%
Molybdenum Mo: 0.15 ~ 0.25%
Learn performance editing broadcast
Hardness: Annealed,147~241HB,42CrMo
Mechanical properties of 4140 round steel:
Tensile strength σb (MPa) : ≥1080(110)
Yield strength σs (MPa) : ≥930(95)
Elongation δ5 (%) : ≥12
Reduction rate of cross-section (%) : ≥45
Impact power Akv (J) : ≥63
Impact toughness value αkv (J/cm2) : ≥78(8)
Hardness: ≤217HB
In order to increase the die life to more than 800 thousand die times, the hardening method of quenching and low temperature tempering can be implemented on the pre-hardened steel. Quenching at 500-600ºC preheat 2-4 hours, and then at 850-880ºC hold heat for a certain time (at least 2 hours), into the oil cooling to 50-100ºC oil air cooling, quenching hardness can reach 50-52HRC, in order to prevent cracking should be immediately 200ºC low temperature tempering treatment, after tempering, hardness can be maintained above 48HRC.
Salt bath vanadium treatment editor
The carbide permeating layer of 4140 steel can be obtained by the neutral salt bath vanadium treatment of 4140 steel.
1. Vanadium compound, the permeating layer has uniform organization, good continuity and density, uniform thickness, dense structure, high microhardness and high wear resistance, surface hardness, wear resistance and anti-adhesion properties are greatly improved.
Second, the solubility of VC in austenite is higher than its solubility in the iron cable body, with the decrease of temperature, VC precipitation from the iron cable body, so that the alloy strengthening and grain refinement, compound layer shows a higher hardness. Steel belongs to high carbon and high chromium leytenite steel, the content of carbide is high, accounting for about 20%, and often presents a strip or network uneven distribution, serious segregation, and conventional heat treatment is difficult to change the state of carbide segregation, which seriously affects the mechanical properties of steel and the service life of die. The shape and size of carbide also have a great influence on the performance of steel, especially the large block sharp Angle carbide has a great effect on the steel matrix, and often becomes the source of fatigue fracture. Therefore, it is necessary to transform the raw material rolled steel to fully break eutectic carbide, so that it is fine and evenly distributed, and the fiber structure is distributed around the cavity or without direction. Thus improving the transverse mechanical properties of steel.
During forging, the billet is upset and drawn several times from different directions, and the "two light and one heavy" forging method is adopted, that is, the billet should be struck lightly at the beginning of forging to prevent fracture, and can be struck at the intermediate temperature of 980 ~ 1 020 ºC. In order to ensure the crushing of carbide,4140 steel has not been changed to forging. Solid solution double refinement treatment is adopted, namely secondary preheating at 500 ºC and 800 ºC, solid solution treatment at 1 100 ~ 1 150 ºC, quenching into hot oil or isothermal quenching, high-temperature tempering at 750 ºC, heating oil at 960 ºC after machining and then final heat treatment. The carbide can also be refined, rounded corners, grain refinement.
Specification for hardening of 4140 steel
Ordinary quenching and tempering specifications: quenching temperature 1000~1050ºC, quenching oil or gas, hardness ≥ 60HRC; The tempering temperature is 160~180ºC, the tempering time is 2h, or the tempering temperature is 325~375ºC, the tempering times is 2~3 times.
Physical properties editor broadcast
1) Critical point temperature (approximate) : Ac1=730°C, Ac3=800°C, Ms=310°C.
2) linear expansion coefficient, temperature in the 20 ~ 100 ° C / 20 ~ 200 ° C / 20 ~ 300 ° C / 20 ~ 400 ° C / 20 ~ 500 ° C / 20 ~ 600 ° C,
Linear expansion coefficient: 11.1×10K/12.1×10K/12.9×10K/13.5×10K/13.9×10K14.1×10K.
3) Elastic modulus: temperature 20°C/300°C/400°C/500°C/600°C,
Elastic modulus of 210000 mpa / 185000 mpa / 175000 mpa / 165000 mpa / 15500 ompa
Process specification for steel 4140
Hot working specification
Heating temperature 1150 ~1200°C, starting temperature 1130 ~1180°C, end temperature > 850 ° C, phi & gt; At 50mm, cool gently.
Normalizing specification
Normalizing temperature 850~900°C, out of the oven air cold.
High temperature tempering specification
Tempering temperature 680~700°C, out of the oven air cold.
Specification for quenching and tempering
Preheating temperature 680 ~700°C, quenching temperature 840~880°C, oil cooling, tempering temperature 580°C, water cooling or oil cooling, hardness ≤217HBW.
Specification for hardening and toughening under - temperature quenching
Quenching temperature 900°C, tempering temperature 560°C, hardness (37±1) HRC
Specification for induction hardening and tempering
Quenching temperature 900°C, tempering temperature 150~180°C, hardness 54 ~60HRC.
Typical application examples edit broadcast
Suitable for making large and medium-sized plastic molds requiring certain strength and toughness.
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