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AISI 8620 Steel is a low alloy nickel, chromium, molybdenum case hardening steel, generally supplied in the as-rolled condition with a maximum hardness HB 255max. SAE steel 8620 offers high external strength and good internal strength, making it highly wear-resistant. Let’s introduce 8620 equivalent steel in this article.

AISI 8620 is American Standard steel, its performance and application keep accordance with Germany, Japan, China, British steel industry standard. We would like to introduce such material in this article.

8620 equivalent:

AISI 8620 equivalent steel of Germany standard grade is DIN 21NiCrMo2 and W-Nr 1.6523. Chemical composition comparison as below table

AISI 8620 substitute steel of China standard grade is GB 20CrNiMo. Chemical compostion comparison as below table

AISI 8620 replacement of Japan standard grade is JIS SNCM220. Chemical composition comparison as below table

OTAI  8620 Steel is from top 3 China steel mill, our supply range as follow

8620 Round Bar: diameter 8mm – 3000mm
8620 Steel Plate: thickness 10mm – 1500mm x width 200mm – 3000mm
8620 Square Bar: 20mm – 500mm
8620 tubes are also available against your detailed request.
Surface Finish: Black, Rough Machined, Turned or as per given requirements.

We can provide a series of sizes of 8620 steel, the following are the main 8620 size:

AISI 8620 size Supply Range

8620 Round Bar: diameter 8mm – 3000mm
8620 Steel Plate: thickness 10mm – 1500mm x width 200mm – 3000mm
8620 Square Bar: 20mm – 500mm
8620 tubes are also available against your detailed request.

Surface Finish: Black, Rough Machined, Turned or as per given requirements.

AISI 8620 Alloy steel, we can supply the round bar, steel flat bar, plate, hexagonal steel bar, and steel square block. AISI 8620 steel Round bar can be sawn to your required lengths as one-offs or multiple cut pieces. 8620 alloy steel Rectangular pieces can be sawn from flat bar or plate to your specific sizes. Ground tool steel bar can be supplied, providing a quality precision finished bar to tight tolerances.

Form of Supply

AISI 8620 alloy steel round bar and flat sections can be cut to your required sizes. 8620 alloy steel ground bar can also be supplied, providing a high-quality tool steel precision ground tool steel bar to your required tolerances. AISI 8620 steel is also available as Ground Flat Stock / Gauge Plate, in standard and nonstandard sizes. Welcome and contact us.

8620 carbon steel is widely used in various industrial fields. About 8620 carbon steel, some people may wonder: 8620 is carbon steel or alloy steel? The following is a brief description of 8620 carbon steel.

First, the following are the difference between Carbon and alloy steels：

Carbon and alloy steels are the most basic and most frequently used steels. They normally have small amounts of carbon and alloying elements. Carbon steels are frequently used as is, without heat treatment of any kind, but can be case hardened. Addition of lead or sulfur improves machinability but is detrimental to weldability, heat treatability, and formability. Steel parts that require no special properties or heat treatment often are madeof this type of steel.
Alloy steels have additional alloying elements and carbon added to improve the mechanical properties and hardenability. The alloying elements allow the steel to form carbon or alloy carbides that improve wear and/or toughness when heat treated.

Brief description of 8620 carbon steel：

SAE 8620 is low carbon case carburizing alloy steel, main contents of it are carbon, nickel, chromium, and molybdenum.

8620 is nickel-chromium-molybdenum alloy steel. It is recommended that the steel be hardened by carburization which gives it a tough core and hard, wear resistant surface. Nickel provides good toughness while the chrome and molybdenum increase through hardness and wear resistance. Uses include machine parts as gears, crankshafts, shafts, gear rings. 8620 has good machinability before carburizing.

8620 carbon steel can also be used (uncarburised) as high tensile steel, which when suitably hardened and tempered can be utilized for various applications requiring good tensile strength and reasonable toughness. Prehardened and tempered (uncarburized) 8620 carbon steel can be further surface hardened by nitriding but will not respond satisfactorily to flame or induction hardening due to its low carbon content.8620 (carburized) is used extensively by all industry sectors for light to medium stressed components and shafts requiring high surface wear resistance with reasonable core strength and impact properties.

8620 carbon steel is extensively used for gears, shafts, crankshafts. Typical uses are Arbors, Bearings, Bushings, Cam Shafts, Differential Pinions, Guide Pins, King Pins, Pistons Pins, Splined Shafts, Ratchets, Sleeves, etc.

We can supply a wide range of 8620 steel, include 8620 round bar,8620 plates and 8620 tubes, welcome and contact us.

 Heat treatment tool steel – The proper heat treatment of the steel can significantly increase the mechanical properties such as hardness, strength, toughness and wear resistance. Electroplating is applied for surface treatment, the precision of the mold is improved, the surface is bright, the demoulding is smoother, and the surface luminosity of the finished product is increased. Therefore, in order to prolong the life of the mold and improve the quality, in addition to pre-selecting appropriate mold materials, the selection of the heat treatment method for the mold is extremely important after processing. The following points are explained.

1.Normalization
This heat treatment is designed to eliminate the coarse grain structure generated by high temperature and high pressure processing such as casting, forging, rolling, etc., and to eliminate the internal stress generated by the processing. The method is to heat the work to a temperature of 30-50°C above the abnormal point AC3 or ACm point, so that it is naturally cooled in the air, as shown in Figure 1. The steel for large-scale construction is used, and after the material is forged into a model, normalization treatment is applied.

2. Annealing
Annealing is to soften the steel, adjust the crystal structure, and remove internal stress. The method is to heat to 30 °- 50 ° C above the AC3 or AC1 metamorphic point, after a suitable time, in the furnace or ash cooling. There are two ways to anneal the mold material.

3. Stress relief annealing
The purpose is to remove the internal stress caused by the processing. Suitable for roughing, medium cutting or mold parts requiring quenching. The stress generated by the metamorphosis of the granules in the granules during quenching will increase. Unless the internal stress is first removed to eliminate internal stress, it will cause a large strain and cause quenching and warping. Even if the parts that are not quenched are subjected to a large amount of heavy cutting, without this treatment, the precision of the dimensional change or warpage will occur due to the residual of the machining stress.

4. Spheroidizing annealing
The purpose is to improve the workability, increase the toughness, prevent quenching and cracking, and turn the carbides in the steel into spherical structures.

5. Quenching
The purpose of quenching is to harden the steel and increase its strength. The method is that the steel is heated to about 30°~50°C above the AC3 or AC1 metamorphic point, and after being kept for a suitable time, it is rapidly cooled in the quenching liquid to produce a high hardness Matian iron structure.

The influence of mold steel on standard parts – Relevant experts believe that the application of mold standard parts will become more and more extensive, and the standardization of molds and the application of mold standard parts can greatly affect the mold manufacturing cycle. The use of mold standard parts not only shortens the mold manufacturing cycle, but also improves mold quality and reduces mold manufacturing costs. At the same time, the prospect of fast economic molds is very broad. Since people require molds to have a shorter production cycle, the development of fast and economical molds has attracted more and more attention. For example, various superplastic materials are developed to make molds; simple molds are made of epoxy, polyester or fillers such as metal and glass. This type of mold has a simple manufacturing process, easy control, low shrinkage, low price, and high life. Automobile cover molds can also be made from cement plastic. Medium and low melting point alloy molds, spray molding molds, electroforming molds, precision molds, laminated molds, ceramic blister molds, and light styling and rapid manufacturing using heat-hardened rubber. Rapid economic molds such as low-cost molds will be further developed. Quick changeovers, quick-change punches, etc. will also grow. In addition, the rapid die change device and rapid test mode device technology using computer control and robot operation will also be developed and improved.

Experts believe that the proportion of medium-pressure molds in the mold industry will continue to increase. With the development of lightweight products such as vehicles and motors, there is an increasing demand for the number, life, and complexity of die-casting molds. With the development of plastic-based steel, plastic-based wood and the precision and complexity of product parts, the proportion of plastic molds will continue to increase, and the accuracy and complexity will increase accordingly.

Tool steel type and performance – OTAI special steel is professional tool steel supplier, we can supply a wide range of tool steel, now let me briefly introduce the types and performance of tool steel.

Tool steel is one of the steel types for making molds such as cold die and hot forging die. The die material is an important part of the material and technology of the mold manufacturing industry. Its variety and quality play an important role in the performance of the mold and the mold manufacturing cycle. Molds are used in a wide range of applications, and the materials are used in a wide range of applications.

Tool steel type:
Tool steel can be generally divided into three categories: cold work tool steel, hot work tool steel, and plastic forming tool steel.
1. Cold work tool steel is mainly used as a mold for press forming a workpiece in a cold state. Such as cold punching die, thread pressing die and powder pressing die. Due to its good wear resistance and toughness, it can be used to make punching dies for stainless steel and high hardness materials.
2. Hot work tool steel is a type of mold that is pressure processed at high temperatures. Such as hot forging die, hot forging dies, etc.
3. Plastic molds, which have many varieties and different requirements for plastic products, have high requirements for performance. Many industrially developed countries have formed a wide range of plastic mold steel series.

Tool steel performance includes:
1. Strength properties, if a mold wants its shape and size under high pressure, it needs to have high hardness, and the mold will bend at high strength, so compressive strength and bending strength are necessary. factor.
2. Resilience, in order to prevent the mold from breaking during the use process, the tool steel has certain toughness requirements.
3. Anti-heat fatigue, due to the existence of high temperature and periodic quenching and rapid heat, we need to pay attention to the thermomechanical fatigue fracture properties of the material.
4. Abrasion resistance, because the mold is subjected to considerable compressive stress and friction during work, it is necessary to have strong wear resistance.

Tool steel manufacturing:

There are many aspects to be paid to the manufacture of tool steel. The precision and manufacturing skills of its processing equipment will affect the quality of tool steel. The guarantee of quality is a necessary condition for expanding market share and will also affect the brand. The production of tool steel is a complicated process that requires high-precision instrumentation. Ordinary coordinate instruments cannot guarantee the accuracy of data, especially for
molds with complex surface structures.

The fluidity should be considered in the manufacturing process of tool steel. The main part is the appropriateness of the temperature during the casting process and the magnitude of the pressure, which determines the accuracy of the shape of the mold. Good equipment is a key factor in determining quality and appearance in order for the mold to meet the requirements.

The conditions that lead to tool steel not meeting the standards are:
First, when the mold is relatively low in temperature, it will make its structure lose and cannot form a fixed shape and style.
Second, if the temperature is too high, the structure will be too tight, which will cause the glue to stick to the mold, and the high the temperature will cause the expansion, and the precision will not be guaranteed. Therefore, it is necessary to control it within a certain range to create perfect tool steel.

Cr12MoV tool steel is a kind of die steel, and Cr12MoV tool steel has high hardenability. It can be completely hardened when the section is 300 ~ 40 0mm or less. It can maintain good hardness and wear resistance at 300 ~ 40 0 ​​°C. The toughness is higher than that of Cr12 steel, and the volume change during quenching is the smallest.

The tempering of the Cr12MoV tool steel is a heat treatment method in which the strain accumulated in the quenched workpiece is relieved by heating, and the hardness is adjusted to improve the toughness. During the tempering process, the carbide precipitates from the hard and brittle martensite formed by quenching, the quenched martensite becomes tough tempered martensite, and the retained austenite in the steel is decomposed to produce two The effect of secondary hardening.

Most of the Cr12MoV tool steels are used at high temperatures, so the secondary hardening type high temperature tempering treatment (500 to 650 ° C) is generally used to obtain the stability of the mold. However, Cr12MoV tool steel for cold work molds is sometimes treated with low temperature tempering at around 200 °C.

The change in size over the years is an important issue for cold work dies. The change in size over the years is a phenomenon in which undecomposed unstable austenite changes with time and expands to cause dimensional change. In general, for every 1% change in retained austenite, the mold size will be 0.01 to 0.015% elongation. This dimensional change will proceed slowly over a few years after heat treatment, even at room temperature. Therefore, this phenomenon becomes a big problem of a cold working die requiring high dimensional accuracy. The method of suppressing the change in size over the years is to reduce the amount of retained austenite or to stabilize austenite.

After the tempering of the Cr12MoV tool steel, the Cr12MoV tool steel is heat treated at about 400 °C to reduce the strain of the unaltered retained austenite in the quenching and tempering, so that the retained austenite is stabilized, and it is difficult to change the size over time.

The hardness of cr12mov tool steel can reach above HRC60.
Hardness is the heat treatment requirement, not a fixed value. There is a limit range. After the quenching temperature of 1010 °C, Cr12MoV is air-cooled and tempered at 200 °C. The hardness can be 58~60HRC, but the prerequisite is reliable material quality. Source, as well as a proven heat treatment technology.
Cr12MoV tool steel
Cold work dies steel, steel hardenability, quenching, and tempering hardness, wear resistance, strength is higher than Cr12. Various cold stamping dies and tools with complex shapes and heavy working conditions, such as punching die, trimming die, piping dies, steel plate deep drawing die, circular saw, standard tools, and gauges, thread rolling die, etc.

Quenching specification:
Ordinary quenching and tempering specifications:
Quenching temperature 1000~1050 °C, hardening or quenching, hardness
≥ 60HRC; tempering temperature 160~180°C, tempering time 2h, or
tempering temperature 325~375°C, tempering times 2~3 times.

Today, we have a nice talking about our company’s steel with a Mexican customer. During the communication process, the customer is quite sure about the chemical composition and quality of our steel. Our company is a professional supplier of tool steel, die steel, and alloy steel.

The following is a brief introduction to tool steel

Tool steel is steel used to make cutting tools, gauges, molds and wear tools. It has high hardness and high hardness and red hardness at high temperatures, as well as high wear resistance and proper toughness.

Tool steels are generally classified into carbon steels, alloy steels, and high-speed steels

The steel used in the manufacture of various cutting tools, cold and hot deformable tools, gages and other tools, collectively referred to as tool steel. Various steels have common requirements, such as high hardness, good wear resistance, and certain toughness and strength, and have their own special requirements, such as red hardness, impact resistance, dimensional stability, thermal fatigue resistance, and good overall mechanical properties, etc. In order to meet these different requirements, steels of various compositions are produced and their performance requirements are met by appropriate heat treatment processes.

High-speed  steel:
High-speed steel is an alloy steel containing C, Mn, Si, Cr, V, W, Mo, Co. And it can be used for high-speed rotary cutting tools, which can wear and high temperature, which is the proportion of Cr, V, W, Mo. In addition, the ratio of Cr and V must not be less than 3%. The P and S content should not exceed 0.030%.

Alloy steel:
The processing methods of alloy tool steel are mainly pressure- machined steel and cutting tool steel. There are many types of alloy tool steels, such as cold work, hot work, non-magnetic, plastic mold steel, etc., while the ratio of Cr and V cannot be too low.

Cold work steel:
Cold steel selection, in practical applications, tool steel is selected according to the main failure mechanism of the mold. It is not enough to choose tool steel to have only knowledge of steel properties. It is also necessary to consider the number of parts produced, the type of material being processed, the thickness and hardness. One of the basic methods for selecting steel is to completely eliminate all failure mechanisms other than wear, and then select the steel with the best wear resistance to meet the production requirements.