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1.2738 plastic mold steel is the German DIN standard material number.
The hardness levels of 1.2311 and 1.2738 plastic mold steel are generally 28-34HRC. 1.2311 is mainly used for small size molds, the thickness is generally up to 400mm. For larger sizes, 1.2738 alloys with Ni added are usually used. When the hardness of 1.2711 is about 42HRC, better polishing performance can be obtained.

1.2738 plastic mold steel is improved on the basis of P20 steel, and 0.9% ~ 1.2% Ni is added on the basis of P20 steel. So its toughness, plasticity and corrosion resistance can be significantly improved. It is a widely used steel for plastic molds in the world. It has good comprehensive mechanical properties and high hardenability. It can make the steel with a larger cross-section more uniform in hardness. It has good polishing performance and a high surface finish.

When the steel is used to make a mold, it is generally tempered first, and the hardness is 28-35HRC (that is, pre-hardened), and then it is made into a mold by cold working and can be used directly. In this way, the performance of the mold is guaranteed, and the deformation of the mold caused by heat treatment is avoided. Therefore, the steel is suitable for manufacturing large and medium-sized plastic molds.

Since P exists in the solid solution of ferrite, it tends to segregate at the grain boundaries. It reduces the toughness of the steel. Therefore, the P content in the steel should be as low as possible.
1.2738 plastic mold steel is mainly used in large plastic molds such as car front bumpers and home appliances. So it has high requirements on isotropy and polishing performance. While S tends to segregate at the grain boundary, increasing the anisotropy of steel, and the resulting Sulfide inclusions reduce the purity of the steel. So the S content in the steel should be as low as possible.

Due to the differences in technical strength and production equipment of various steel mills, the quality level of various types of 1.2738 plastic mold steel on the market varies. So it really is very important and necessary to find a supplier with very good reputation. And we with over 21 years’ pre and after sales business on the special steel, we could help distributor and end users to avoid all possible cheat.

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In current，There are three main materials for drill rods: 42CrMo4 steel, 40Cr, C45.

42CrMo4 steel is an ultra-high strength steel with high strength and toughness

In current，There are three main materials for drill rods: 42CrMo4 steel, 40Cr, C45.

42CrMo4 steel is an ultra-high strength steel with high strength and toughness, good hardenability, no obvious temper brittleness, high fatigue limit and multiple impact resistance after quenching and tempering, and good low temperature impact toughness. The steel is suitable for manufacturing large and medium-sized plastic molds that require certain strength and toughness.

These characteristics ensure that the hardness of the finished drill rod can reach a high level, at the same time, it has good toughness and good resistance to multiple impacts. The hardness of the drill rod is good, the wear resistance is good, the hardenability is good, and the hardness of the surface of the drill rod and the core can be guaranteed. The absence of tempering brittleness reduces the fracture rate of the drill rod, and the toughness is good. The ability is good, and it is guaranteed that the tail of the drill rod and the piston are not easy to knock off the block. Taken together, it is an ideal material for making drill rods. But the price of raw materials is higher. Therefore, the price of the finished rod is higher. However, the comprehensive cost performance is relatively high.

40Cr is not an ultra-high-strength steel

40Cr is far inferior to 42CrMo4 steel in tempering brittleness, fatigue limit and resistance to multiple impacts, but it has good toughness and hardenability. Therefore, the brazing rod made of it as a raw material is not as good as 42CrMo4 in terms of wear resistance and tail impact. Because it has good toughness, the drill rod is not easy to break. At the same time, the cost of its raw materials is lower than 42CrMo4, so the price of the finished drill rod is more affordable. It is also the most popular type of brazing rod currently on the market. However, in the mine operation, the wear will be faster and the drill rod will be softer. It is not very suitable if you encounter harsh working conditions and environment.

The mechanical properties of C45 steel

Quenching has low hardenability, and it is easy to cause uneven hardness of the drill rod during heat treatment, resulting in deformation or even cracking. The hardness after quenching is about 42 degrees, which is much lower than the 55 degrees of 42CrMo brazing rod. Therefore, the wear resistance is extremely poor. At the same time, the stability of the drill rod is also very poor, and it is easy to break and break the block. But because of its low price, the materials are produced in many places. Therefore, some manufacturers choose when manufacturing low-cost drill rods.

The 42CrMo4 steel wear resistance is good

It is not easy to break and break the block, but the market price is relatively high, and the overall cost performance is the best. It belongs to a good grade in the current market.40Cr as the raw material is affordable and not easy to break, but it is not as good as 42CrMo4 in wear resistance and tail knockout. The real cost performance of mine operations is not higher than 42CrMo4.

Price

The price of the drill rod made of C45 steel is low, but the mechanical performance is far from meeting the requirements of the drill rod. It is not wear-resistant, easy to break, and easy to drop. It is a low-end product in the market.So is there any better material? Of course there are, but because of the high price of raw materials and the difficulty of processing, the finished product of the drill rod is expensive, but it is not as cost-effective as 42CrMo4.

Ms Sharon Wan

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The material of 42CrMo4 for gear forgings must first meet the requirements of working conditions.

DIN 42CrMo4 for gear equivalent material

♦JAPAN♦ : JIS SCM440 alloy steel

♦American♦ : AISI/ASTM 4140 steel alloy

♦CHINA♦ :  GB 42CrMo steel

♦BRITISH♦ : BS 708M40

The material of 42CrMo4 for gear forgings must first meet the requirements of working conditions.

The requirements of working conditions are the factors that should be considered first when selecting gear forging materials. Alloy steel is often used to make gear forgings with high speed, heavy load and working under impact loads, such as gears used in aircraft. High reliability is required, so alloy steel with high mechanical properties must be selected. If the gear size is required to be as small as possible, surface-hardened high-strength alloy steel should be used. The gear transmission in mining machinery generally has large power, low working speed, and extremely high dust content in the surrounding environment. Therefore, cast steel or cast iron are often selected. The power of household and office machinery is very small, but it requires stable transmission, low noise or no noise, and can work normally with little or no lubrication. Therefore, engineering plastics are often used as gear materials.

The choice of 42CrMo4 for gear forging materials should consider the gear size

Blank forming method and heat treatment process. Large-sized gears generally use cast blanks, and cast steel or cast iron can be used as gear materials. Gears with high requirements for medium or below medium size often use forged blanks, and can be made of forged steel. When the size is small and the requirements are not high, round steel can be used as the blank.

Function of 42CrMo4 for gear

42CrMo for gear steel is a high quality Quenched and Tempered Alloy Structural steel . It belong to the high quality medium carbon alloy steel, Oil Quenched & Tempered Hardenss is 28-34 HRC . 42CrMo Annealing delivery hardenss less than 250HB . This materials was the best choose for produce bolt and screw .

Ms Sharon Wan

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42CrMo4 steel gear forgings have higher fatigue strength limit and resistance to multiple impacts.

42CrMo4 steel gear compared with 40Cr forged gears

Compared with 40Cr forged gears, 42CrMo4 forged gears are better than the former, especially the hardenability is higher than 40Cr steel gears. After quenching and tempering, 42CrMo4 steel gear forgings have higher fatigue strength limit and resistance to multiple impacts, and the low temperature impact toughness is good.

Chemical composition

The main chemical composition (mass fraction) of forged gear 42CrMo4 steel is: 0.38% ~ 0.45% c, 0.17% ~ 0.37% Si, 0.50% ~ 0.80% Mn, 0.90% ~ 1.20j% Cr, 0.15% ~ 0.25% Mo, ≤ 0.30% Ni, ≤0.030% P, ≤0.030% S.

The phase transition points are: Ac1730 ℃, Ac3800 ℃, Ms310 ℃.

Forging 42CrMo4 steel gears, the initial forging temperature is 1130 ~ 1180 ℃, and the final forging temperature is 850 ℃. After forging, the diameter size is more than 50mm and it needs to be cooled slowly.

The carbon content of 42CrMo4 steel gear is kept at about 0.42%, which ensures that the steel has a good combination of strength and toughness. The addition of Cr and Mo elements is mainly to improve the hardenability of steel. When quenching and heating, Cr and Mo elements are completely dissolved in austenite to improve the hardenability of steel. After quenching, Cr and Mo elements solid solution strengthen the matrix structure and improve the tempering stability of the matrix structure. During high temperature tempering, some Cr and Mo elements diffuse from the matrix structure to the precipitated cementite Fe3C to form alloy cementite (Cr, Mo, Fe) 3C. In addition, the addition of Mo element can eliminate the temper brittleness. Adding a small amount of Ni element can improve the toughness of steel.

There are many factors to consider when choosing. In general, the working conditions of gear forgings are different, and the damage form of gear teeth is different. It is the basis for determining the calculation criterion of gear strength, selecting materials and heat treatment.

–                                                                                                 -To be continued

Ms Sharon Wan

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There are many types of materials for gear forgings. The commonly used materials for gear forgings are: 40Cr, 42CrMo4, 20CrMnMo, 20CrMnTi, etc.

42CrMo4 forged and 40Cr forged gears are mostly the most large-scale gear forgings in the lifting industry.

The small piece has no owner (reference). Most gears require gears to improve quality. The heat treatment hardness of the gears can reach the best performance at 38-42HRC. The toughness of 42CrMo4 is much better than 40Cr, because the former has better heat treatment hardenability, which is closely related to its material. Also, the strength at the same hardness is very close. In the best performance, the tensile strength of 40Cr is 60 ~ 75 kg / mm ;the yield strength is 35 ~ 55 kg / mm; the tensile strength of 42CrMo4 forged is 110 kg / mm;the yield strength is 95 kg / mm, obviously 42CrMo4 performance is much better than 40Cr performance.

Hardness

40Cr material has good hardenability, it can be hardened to 28 ~ 60mm in diameter when water quenching, and 15 ~ 40mm in diameter when oil quenching. After tempering, the material has good comprehensive mechanical properties, and has good low notch sensitivity and low temperature impact toughness. After 40Cr gear forgings are quenched and tempered, they are often subjected to surface induction hardening or nitriding. When the hardness is 174 ~ 229HBS, the cutting performance is better, the relative cutting workability is 60%, the carbon content of 40Cr forgings is maintained at about 0.40%, to ensure that the steel has a good combination of strength and toughness. The addition of Cr element is mainly to improve the hardenability of steel. When quenching and heating, Cr element is completely dissolved in austenite, which improves the hardenability of steel. After quenching, Cr element solid solution strengthens the matrix structure and improves the tempering stability of the matrix structure. During high temperature tempering, some Cr elements diffuse from the matrix structure to the precipitated cementite Fe3C to form alloy cementite (Cr, Fe) 3C.

Chemical components

The main chemical components of 40Cr steel for gear forgings are: 0.37% ~ 0.44% C, 0.17% ~ 0.37% Si, 0.50% ~ 0.80% Mn, 0.80% ~ 1.10% cr, ≤0.035% P, ≤0.035% S

The phase transition points are: Ac1770 ℃, Ac3805 ℃, Ms328 ℃.

The initial forging temperature of 40Cr gear forgings is 1100 ~ 1150 ℃, and the final forging temperature is 800 ℃. After forging, the size needs to be cooled slowly when the size is more than 60mm.

-To be continued

Ms Sharon Wan

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What is the role of cr (chromium) in 42CrMo4 seamless steel pipe? Use chromium, the chemical symbol Cr, and the element is steel gray metal.

What is the role of cr (chromium) in 42CrMo4 seamless steel pipe?

The element name comes from the Greek, which originally meant “color” because chromium compounds all have color. Obtained with carbon reduction. The content of chromium in the crust is 0.01%, ranking 17th. There is no free chromium in nature, mainly in chromite. In the periodic table, it belongs to group ⅥB. The atomic number of chromium is 24, the atomic weight is 51.9961, and body-centered cubic crystals. The oxidation number is 6, 5, 4, 3, 2, 1, −1, −2, −4 and it is the hardest metal.

The decisive role of chromium in stainless steel gold

42CrMo4 seamless steel pipe is only one element that determines the nature of stainless steel. This is chromium. Each stainless steel contains a certain amount of chromium. To date, there is no chromium-free stainless steel. The fundamental reason why chromium becomes the main element that determines the performance of stainless steel,it’s the addition of chromium to steel, as an alloy element promotes the development,the internal contradictory movement in favor of resisting corrosion damage. This change can be explained from the following aspects: ① Chromium increases,the electrode potential of the iron-based solid solution ② Chromium absorbs iron electrons to passivate the iron, the passivation is due to the anode reaction is prevented,and the corrosion resistance of the metal and alloy is improved phenomenon. There are many theories that constitute the passivation of metals and alloys, mainly including thin film theory, adsorption theory and electron arrangement theory.

Chromium is used to make stainless steel, auto parts, tools, tapes and video tapes. Chrome plated on the metal can prevent rust, also known as dormitory, strong and beautiful.

Chromium can be used to make stainless steel. The color of red and emerald also comes from chromium. As the most important metal in modern technology, chromium-nickel steel fused in different percentages is ever-changing, and there are many kinds of incredible. The toxicity of chromium is related to its existing valence state. Hexavalent chromium is 100 times more toxic than trivalent chromium ,and it can be easily absorbed by the body and accumulated in the body. Trivalent chromium and hexavalent chromium can be converted into each other. Natural water does not contain chromium; the average concentration of chromium in seawater is 0.05ug / l; lower in drinking water. The sources of chromium pollution include sewage discharged from the processing of chromium-bearing ores, metal surface treatment, leather tanning, printing and dyeing, etc.

Ms Sharon Wan

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Acero M2

El acero para herramientas M2 es acero de alta velocidad de tungsteno-molibdeno con una composición de carbono bien equilibrada y alta tenacidad.

¿Qué es el Acero M2?

El acero para herramientas M2 es acero de alta velocidad de tungsteno-molibdeno con una composición de carbono bien equilibrada y alta tenacidad. También se llama acero JIS SKH51 y DIN 1.3343. Es fácil sobrecalentar, controlar la temperatura de calentamiento de enfriamiento es necesario y los requisitos de protección del tratamiento térmico son estrictos. Se usa ampliamente para hacer herramientas de corte debido a su gran dureza y resistencia al desgaste. Ha reemplazado el acero de alta velocidad T1 en la mayoría de las aplicaciones, se ha convertido en la primera opción del cliente debido a su gran rendimiento y relación de precio de rendimiento extremadamente alto. Las propiedades del acero y el tratamiento térmico son las siguientes.

1.3343 Características del acero

1. Dureza (estado original de fábrica): ≤255HB
2. Temperatura de endurecimiento: 1220 ℃ -1240 ℃
3. Dureza (después del tratamiento térmico): ≤63HRC
4. Es una gran opción en aplicaciones de corte debido a su gran resistencia al desgaste y tenacidad.
5. Carburo distribuido uniformemente y alta tenacidad.
6. Se puede utilizar para hacer fresas, escariadores, brochas, cortadoras de engranajes y otras herramientas de la industria.

Tratamiento térmico de acero M2 y producido

Maquinabilidad

La conformación de aceros para herramientas M2 puede ejecutarse utilizando estrategias de rectificado. Pero, que tiene mala capacidad de molienda. Por eso se les llama acero para herramientas de maquinabilidad «mediana» en condiciones de recocido. La maquinabilidad de estos aceros es solo el 50% de la de los aceros para herramientas de endurecimiento por agua o grupo W fácilmente mecanizables.

Recocido

Calentar a 1600 ° F, remojar completamente al calor. El horno se enfría 25 ° F por hora a 900 ° F, el aire se enfría a temperatura ambiente. Dureza recocida aproximada 241 Brinell máximo.

Alivio de la tensión del material sin endurecer: Caliéntelo lentamente de 1200 a 1250 ° F. Remoje durante dos horas por pulgada de espesor al calor. Enfriamiento lento (horno frío si es posible) a temperatura ambiente.

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OT718  mold steel

After forging and rolling, the structure is dense, 100% ultrasonic inspection, no pores, pinhole defects.

1. a) The template of the large mold, the high surface requires household appliances.
2. b) Suitable for large mirror plastic molds, such as automobiles, home appliances, audio and video products, etc.
3. c) Can be used for plastic molds with mirror polishing requirements, suitable for injection molds, blow molds for PA, POM, PS, PE, PP, ABS plastics.
4. d) High polishing and demanding mold cavity.                                                                                                                                Hardened

In order to improve the service life of the mold to more than 800,000 mold times, the pre-hardened steel can be implemented by hardening and low-temperature tempering. When quenching, first preheat at 500-600 ℃ for 2-4 hours, and then keep it at 850-880 ℃ for a certain period of time (at least 2 hours), put it in oil and cool it to 50-100 ℃, and leave it to air-cool. -52HRC, in order to prevent cracking, a low temperature tempering treatment at 200 ° C should be performed immediately. After tempering, the hardness can be maintained above 48HRC.

Collapse this section nitriding

Nitriding treatment can obtain high hardness surface layer structure, the hardness of the surface layer after nitriding reaches 650-700HV

(57-60HRC) The life of the mold can reach more than 1 million times. The nitrided layer has the characteristics of dense organization and smoothness. The mold release property and the resistance to humidity and alkali corrosion are improved.

Quenching and tempering

Quenching temperature 840 ~ 870 ° C, tempering temperature 200 ~ 500 ° C, hardness 50 ~ 55HRC

Edit the material properties of this paragraph

Folding physical properties

(Sample hardness 340HBW, at room temperature and high temperature)

1) Temperature 20 ° C / 200 ° C / 400 ° C, density 7.8g / cm / 7.75g / cm / 7. 7g / cm.

2) Temperature 20 ~ 200 ° C / 20 ~ 400 ° C, coefficient of linear expansion: 12.6 × 10K / 13.5 × 10K.

3) Temperature 20 ° C / 200 ° C / 400 ° C, thermal conductivity 29.0W · (m · K) /29.5W· (m · K) /31.0W· (m · K)

4) Temperature 20 ° C / 200 ° C / 400 ° C, elastic modulus: 205000MPa / 200000MPa / 185000MPa

Folding mechanical properties

(Sample hardness 340HBW)

1) Temperature 20 ° C / 200 ° C / 400 ° C, tensile strength 1100MPa / 1050MP8 / 850MPa.

2) Temperature 20 ° C / 200 ° C / 400 ° C, conditional yield strength 980MPa / 925MPa / 770MPa.

3) Temperature 20 ° C / 200 ° C / 400 ° C, reduction in area of ​​49% / 51% / 52%

4) Temperature 20 ° C / 200 ° C / 400 ° C, elongation 13% / 14% / 16%

5) Temperature 20 ° C / 200 ° C / 400 ° C, impact toughness (≥) 20J / cm / 32J / cm / 42J / cm

Critical temperature

critical point

Temperature (approximate) / ℃

Expand the expansion coefficient of this paragraph

Temperature / ℃

Linear (expansion) expansion coefficient / C

Edit the thermal conductivity of this paragraph

Temperature / ℃

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1.2738 mold steel

1.2738 is a very common German standard plastic mold steel, usually referred to as 738 for short.

Performance characteristics

① Excellent polishing and photoetching performance;

②Good machining performance;

③ High purity and uniformity;

④ Uniform hardness;

⑤ Follow-up nitriding treatment or local flame quenching can be used to improve surface strength and surface wear resistance and reduce surface failure.

Compared with the traditional plastic mold steel P20, 1% nickel is added to OT718, which has better toughness and hardenability, and performs better in molds with large cross-section sizes. This type of steel is suitable for large-scale, especially thicker than 400mm, plastic molds that require uniform hardness, high toughness, and good surface polishing performance, such as TV frames and back shells, copier cases, bumpers, shock absorbers, instrument panels, etc. Large molds, as well as trash can molds, die-casting mold holders, etc.

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34CrNiMo6 round steel, does this kind of steel suitable for your company? It is the hot sales of the Otai company. Last year, we sold a lot of steel abroad .why clients repeat the order from our company? I want to share some information about the 34CrNiMo6 with you.

34CrNiMo6 round steel, does this kind of steel suitable for your company? It is the hot sales of the Otai company. Last year, we sold a lot of steel abroad .why clients repeat the order from our company? I want to share some information about the 34CrNiMo6 with you.

One of our clients from Singapore bought the 34CrNiMo6 round steel from our company .this is a company served the marine and offshore industry .specialising in marine pipes and fittings and engineering services. 34CrNiMo6 steel is the perfect material applies to the requirement of their company. Our customer is satisfied with our product.

34CrNiMo6 Alloy Steel is a quenching and tempering steel with high strength, high toughness, and good hardenability. A heat treatable, low alloy steel containing nickel, chromium, and molybdenum as per DIN Germany standard.

34CrNimo6 steel has high strength, high toughness, and good hardenability. EN / DIN 34CrNiMo6 alloy steel has the stability of resistance to overheating, but the white sensitivity of 34CrNiM06 is high. It also has the temper brittleness, so the weldability of 34CrNiMo6 material is poor. The steel 34CrNiMo6 needs high temperature preheating before welding to eliminate the stress after welding processing.

Application of 34CrNiMo6 round steel

34CrNiMo6 alloy structural steel is used in ships, vehicles, aircraft, missiles, weapons, railways, bridges, pressure vessels, machine tools, etc. 34CrNiMo6 European standard alloy structural steel grade, corresponding to China’s grade 34Cr2Ni2Mo, is a typical difficult-to-machine material, widely used in the manufacture of engine camshafts and connecting rods and other important parts.

Mr Jack Tan

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