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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.

1. Mold steel Hardness and red hardness (thermal stability)
Hardness is an important performance indicator for mold steel. The mold should be able to maintain its shape and size without rapid changes under the action of compressive stress. Therefore, the heat- treated mold should have sufficiently high hardness, such as a cold work tool, the hardness is generally above HRC60, and the hardness of the hot work tool can be appropriately reduced, generally in the range of HRC 42~50.
Red hardness means that the mold can maintain stable structure and performance under heat or high temperature working conditions, and has the ability to resist softening, and maintains a sufficiently high hardness at 600~600 °C. The red hardness of steel is mainly determined by the chemical composition and heat treatment system of steel, which is an important performance index of hot work die steel.

2. Mold steel Wear resistance
The mold is subjected to considerable compressive stress and friction during operation, and the mold is required to maintain its size and shape under such conditions, and is durable. The mold is mainly subjected to sliding friction during work, and its wear condition is very complicated. The wear resistance of the mold depends not only on the composition, structure, and performance of the steel, but also on the working temperature, load (pressure) state, lubricating medium, etc. relationship. Increasing the hardness of the steel is beneficial to improve the wear resistance of the steel. However, after a certain hardness value, the effect of increasing the hardness on the wear resistance is not significant.
3. Mold steel Strength and toughness
The mold is subjected to maximum load during operation and complex stresses such as impact, vibration, torsion, and bending. Heavy-duty molds tend to be damaged in advance due to insufficient strength and insufficient toughness, causing edge or partial breakage of the mold.
Therefore, maintaining the mold steel with sufficient strength and toughness is beneficial to prolong the life of the mold. However, the grain size of the steel and the amount, size and distribution of the carbides in the steel, as well as the amount of retained austenite, have a great influence on the strength and toughness of the steel. For example, as the grain size in the steel increases and the unevenness of carbide distribution increases, the strength of the steel decreases, and the effect on toughness is more pronounced. The practice has shown that, according to the conditions of use and performance requirements, the chemical composition, microstructure, and heat treatment process of the mold steel can be reasonably selected, and the best combination of strength and toughness can be obtained.
In addition, for mold steel, it is also necessary to consider high temperature strength, thermal fatigue conduction, thermal conductivity, and corrosion resistance according to the working conditions of various molds.
Since most of the die steel is used in high hardness, high strength, high wear resistance and sufficient toughness, the metallurgical quality of the die steel is required to be high, and the gas content in the steel, non-gold inclusions and harmful elements (sulfur) should be minimized. , phosphorus, etc.), at the same time, in order to ensure the steel has good performance, it must be subjected to correct hot pressing (forging, rolling) to change the shape of the section, change the as-cast microstructure and properties, and then be processed by cold cutting. The mold of a certain shape is subjected to final heat treatment (normalizing, quenching and tempering) in order to obtain the required performance of the mold. Therefore, the process performance of die steel is also a very important factor for mold manufacturing.

D2 mold steel high wear-resistant, micro-deformation cold work die steel, wind-hard tool steel, carbon content up to 1.5%, chromium content is higher than 11.5%, heat treatment hardness up to 60HRC. D2 steel can be used to produce cold work die steel with large cross section, complex shape, high impact force and high wear resistance, such as silicon steel sheet die, cold cut scissors, trimming die and so on. So do you know his strengths and application examples?

D2 mold steel advantage:
1. Good processability and stable heat treatment size
2, excellent machining type
3, when the hardness is hard, excellent dimensional stability
4, after hard and tempering, a good match between high surface
hardness and body toughness

D2 mold steel Application examples:
It is used for drawing the deep drawing die of the refrigerator compressor, and the quenching hardness is 56~58HRC.
In order to improve the service life of the flat steel rolled material of D2 cold work die, the wear resistance and impact toughness of the steel are greatly improved by the method of adding rare earth, thereby achieving the purpose of improving the service life of the flat die flat steel.
Since the content of V and Mo in D2 steel is higher than that of Cr12MoV steel, it has better comprehensive performance, and the traditional Cr12MoV steel will be gradually replaced.
The rolling wheel made of D2 steel and the cold stamping die of the Taiwan adjusting plate can increase the service life by 5-6 times compared with the Cr12MoV steel.

DC53 heat treatment hardness is higher than SKD11, high temperature (520-530 °C) can reach 62-63HRC high hardness after tempering, DC53 exceeds SKD11 in strength and wear resistance.
The toughness is twice that of SKD11. The toughness of DC53 mold steel is prominent in cold-working die steel. The tools made with DC53 rarely crack and crack, which greatly improves the service life.
The residual stress after the wire cutting process is small, the residual stress is reduced by the high-temperature tempering, and the crack and deformation after the wire cutting process are suppressed.
Machinability and abrasiveness exceed those of SKD11. DC53 mold steel is superior to SKD11 in terms of machinability and abrasiveness. The use of DC53 mold steel increases tool life and reduces machining processes.

use:
1. Punching mold, cold forming mold, cold drawing mold
2. Forming rolls, punches

Precision stamping die
Precision blanking die for wire cutting and stamping die for various purposes
Tool for plastic deformation of difficult-to-machine materials
Cold forging, deep drawing, and boring die
other
High-speed punching punch, stainless steel plate punch

Practical features:
DC53 cold work die steel
(1) Machinability and good abrasiveness.
The machinability and the abrasiveness are superior to those of the SKD11, so the processing tool has a long life and the number of processing hours is relatively low.
(2) Advantages of heat treatment
Quench hardening is higher than SKD11, so it can improve the defects of insufficient hardness during vacuum heat treatment.
(3) Advantages of online cutting processing
High-temperature tempering can reduce the residual stress and eliminate the residual Worthfield iron, which can prevent the cracking and deformation of the wire cutting process.
(4) Advantages in surface hardening treatment
The surface hardness after surface hardening is higher than that of SKD11, so the mold performance can be improved.
(5) Advantages in repairing welding operations
Since the preheating and post-heating temperatures are lower than SKD11, the repair welding operation is relatively simple.

When purchasing mold steel, it is necessary to first consider whether some basic properties of the mold steel can be adapted to the needs of the manufactured mold. In general, the hardness, strength, toughness, wear resistance and polishing of steel are very important. These properties can comprehensively reflect the comprehensive performance of the die steel, and determine the application range to a certain extent. According to statistics, the early failure of molds is about 10% due to improper selection of mold steel and internal defects, and about 50% caused by improper heat treatment. Therefore, it is of great significance to correctly select mold steel with good quality.

1. Hardness requirements of mold steel

The working state of the mold is complicated during work. For example, the hot working mold usually undergoes alternating stress under the exchange temperature field, so it should have good resistance to softening or plastic deformation, and can still be used in long-term working conditions. Maintain the shape and dimensional accuracy of the mold. For the cold work die, the hardness is generally selected above 56HRC-62HRC, while the hot work die is especially a mold that requires high thermal fatigue resistance, and the hardness is usually around 45HRC-52HRC. For plastic molds, the general hardness requirement is around 28HRC-36HRC.

2. Mold steel strength and toughness requirements

During the forming process, the parts are subjected to huge loads such as impact and distortion, especially modern high-speed stamping, high-speed precision forging and liquid forming technologies, as well as the development of one-shot forming technology. If the strength and toughness of the die steel are not enough, it may cause the edge or partial collapse, chipping or fracture of the cavity to fail early, so the mold should have high hardness and toughness after heat treatment.

3. Mold steel wear resistance requirements

When the mold part is formed, the mold steel and the mold cavity surface move relative to each other, causing the surface of the cavity to wear, so that the dimensional accuracy, shape and surface roughness of the mold is changed and fail. Wear is a complicated process, and many influencing factors depend largely on the chemical composition inhomogeneity, microstructure, and mechanical properties of the die steel.

4. Fatigue performance requirements of mold steel

When the mold is working, it is subjected to the alternating stress of mechanical shock and thermal shock. During the working process of the hot working mold, the thermal alternating stress causes the mold to crack more obviously. Cracks caused by stress and temperature gradients often result in the rapid propagation and expansion of shallow and fine cracks on the surface of the cavity leading to mold failure. In addition, the chemical composition of steel and the unevenness of the structure, metallurgical defects such as non- metallic inclusions, pores, microcracks, etc. in the steel can cause the fatigue strength of the steel to decrease, because under the action of alternating stress, first These weak areas produce fatigue cracks and develop into fatigue damage.

5. Polishing requirements for mold steel

Steel with excellent polishing performance can throw a mirror effect without creases or lines. In general, steels with good polishing properties have high hardness.

P20 and SKD11 mold steel

First, sufficient strength, wear resistance, sufficient hardened layer and strength, toughness, surface hardness and the like.
Although it is not required to be as high as a cold work die, it should meet the requirements for use.
Second, the cold and hot processing performance is good, the surface roughness value is low, the good mirror polishing performance, the surface pattern etching performance and the corrosion resistance, the heat treatment deformation, the metallographic structure, and the mold size are stable.
It has high-temperature strength, toughness, hardness and wear resistance, and has high tempering stability and excellent heat fatigue resistance. High hardenability to ensure that the mechanical properties of the entire section are basically the same.

P20 and SKD11 mold steel

The reason for the high hardening is that it contains about 1.1% of C carbon, so it can be hardened to HRC63 in heat treatment, and it is greatly improved by adding many other elements such as chromium, molybdenum, vanadium, cobalt, etc. P20, SKD11 Hardenability of die steel.
Excellent thermal conductivity, so that heat can be transmitted out as quickly as possible to avoid excessive cavity temperature. Good oxidation resistance.