H13 Hot Work Mold Steel

One. Product Description

H13 is Hot Work Mold Steel, which is made of carbon steel by adding alloying elements, and implements the GB/T1299-2014 standard. Uniform Numerical Code T23353; 4Cr5MoSiV1 grade. It has good comprehensive performance at medium temperature (~600°), high hardenability (hardenable in air), low heat treatment deformation rate, and its performance and service life are higher than 3Cr2W8V. It can be used for mold forging hammer forging mold, aluminum alloy Mold-casting mold, hot extrusion mold, high-speed precision forging mold and forging mold, etc.

Two. Quality Standard

GB/T1299-2000 Standard Specification

Three. Product Specifications

Four. Equivalent Grade of H13 Mold Steel - For Reference Only

Five. Product Features and Uses

Features:

1. Has high hardenability and high toughness.

2. Excellent thermal crack resistance, water cooling can be used in the workplace.

3. The wear resistance is moderate, and the surface hardness can also be improved by carburizing or nitriding, but the thermal crack resistance should be slightly reduced.

4. Because of its low carbon content, the secondary hardening ability during tempering is poor.

5. It has softening resistance at higher temperature, but when the use temperature is higher than 540℃ (1000°F) (that is, the working temperature is 540℃), the hardness will drop rapidly.

6. Heat treatment deformation is small.

7. Medium and high machinability.

8. Moderate decarburization resistance.

Use:

H13 mold steel is mainly used to manufacture high impact load forging molds, hot extrusion molds, precision forging molds, aluminum copper and its alloy Mold-casting molds.

Six. Product Detailed Information

H13 mold steel belongs to electroslag remelting refined steel. The steel has high hardenability and resistance to hot cracking. High vanadium content, good wear resistance, good heat resistance. It has good strength and hardness, wear resistance and toughness. In addition, the provided H13 mold steel also has excellent comprehensive mechanical properties and high tempering stability, hardenability and hot crack resistance.

H13 mold steel is mainly used in the manufacture of high impact load forging molds, hot extrusion molds, precision forging molds, aluminum-copper and its alloy Mold-casting molds. It is a high-quality steel improved on the basis of the American H13 gas quenching hardening hot work mold steel. Its properties and uses are similar to 4Cr5MoSiV1 mold steel. H13 mold steel is customized for Fushun Special Steel, with high vanadium content and moderate temperature. The measured performance at 600 degrees is slightly better than that of Fincola H13 mold steel. It is a relatively reliable brand in hot work mold steel in recent years. For a long time, this data has been verified by many demanding foreign companies.

The carbon content of the steel determines the hardness of the hardened steel matrix, which can be known by comparing the relationship between the carbon content of the steel and the hardness of the hardened steel. The quenching hardness of H13 mold steel is about 55HRC. For the mold, part of the carbon in the material enters the steel matrix to cause solid solution strengthening, and another part of the carbon will combine with the carbide forming elements in the alloying elements to form alloy carbides. For hot work mold steel, in addition to a small amount of residual alloy carbides, it is also required to disperse and precipitate on the quenched martensite matrix during the tempering process, resulting in secondary hardening and tempering of uniformly distributed residual alloy carbides. Martensite. The organization determines the properties of the hot work mold steel. H13 mold steel undergoes strict technical checks and professional smelting in the refining process to ensure its excellent performance and purity.

Control measures and heat treatment

It can be seen from the chemical composition and microstructure characteristics of H13 mold steel that the heat treatment process has a great influence on the microstructure and properties of H13 mold steel. In order to prevent the early failure of H13 mold steel, prolong the service life and improve the economic benefits, the hot working process must be formulated scientifically and reasonably.

Forging process

H13 mold steel has high alloying element content, poor thermal conductivity, and low eutectic temperature, which is easy to cause overburning. For billets with larger diameters, it should be preheated in the range of 800~900℃, and then heated at the initial forging temperature of 1065~1175℃. When forging, the total forging ratio is greater than 4. The preheating treatment of H13 mold steel and mold blanks supplied in the market are all annealed and heat treated in steel mills to ensure that they have good metallographic structure, proper hardness and good machinability. There is no need to anneal again, but the manufacturer destroys the original structure and properties after forging, increases the forging stress, and needs to be re-annealed.

Spheroidizing annealing process

The purpose of the spheroidizing annealing process is to homogenize the structure, reduce the hardness, improve the cutting performance, and prepare the structure for quenching and tempering. The spheroidizing annealing process is 845~900℃ heat preservation (1h+1min)/mm, then furnace cooled to 720~740℃ isothermal (2h+1min)/mm, and finally furnace cooled to 500℃ air cooling. The spheroidized annealed structure is granular pearlite, and the hardness is less than 229HBS. The spheroidization quality can be evaluated according to the GB/T1299-2000 standard first-level diagram.

Quenching and tempering process

The best heat treatment process for H13 mold steel is oil quenching or stage quenching after heating at 1020~1080℃, and then secondary tempering at 560~600℃. The microstructure is tempered troostite + tempered sorbite + residual carbide microhardness 48~52HRC. For Mold-casting molds with high hot hardness requirements, the upper limit heating temperature can be used for quenching. Molds (hot forging molds) that require toughness can be quenched at the lower heating temperature.

Chemical heat treatment

If H13 steel is gas nitrided or nitrocarburized, the mold can be further strengthened, but the nitriding temperature should not be higher than the tempering temperature to ensure that the core strength is not reduced, thereby improving the service life of the mold.

Isothermal spheroidizing heat treatment

Heating at 860~890℃ for 2 hours, cooling to 740~760℃ for 4 hours, furnace cooling to about 500℃.

Pursue the quenching process with good toughness

Heating temperature 1020~1050℃, oil cooling or air cooling, hardness 54~58HRC ,The quenching process that pursues thermal hardening.

Heating temperature 1050~1080, oil cooling, hardness 56~58HRC.

The recommended tempering temperature is 530~560℃, and the hardness is 48~52HRC.

The tempering temperature is 560~580℃; the hardness is 47~49HRC, and the tempering should be carried out twice.

When tempering at 500 ℃, the secondary hardening peak of tempering appears, the tempering hardness is the highest, and the peak value is around 55HRC, but the toughness is the worst. Therefore, the tempering process should be avoided at around 500 °C. According to the needs of the mold, it is best to temper in the range of 540~620℃. Quenching heating should be preheated twice at 600~650℃ and 800~850℃ to reduce the thermal stress during heating.

Delivery hardness: 235HB (can be customized).