AISI H13 and SKT4-Which Is Better For Hot Work Mold?

 

ASTM A681-AISI H13 and JIS G4405 SKT4 Steel,  Both are Hot Work Alloy Tool Steel.  all can used in Hot Forged mold steel Products.  Typical Application have Impact load large forging die, hot extrusion die, precision die; Aluminum, copper and its alloy die-casting mould. But H13 VS SKT4, Which is better for Hot work Mould Steel?

 

AISI H13 and SKT4 Steel chemical composition

C Si Mn S P Cr Mo V
AISI H13 0.32～0.45 0.80～1.20 0.20～0.50 ≤0.030 ≤0.030 4.75～5.50 1.10～1.75 0.80～1.20
JIS SKT4 0.50～0.60 0.10～0.40 0.60～0.90 ≤0.030 ≤0.020 0.80～1.20 0.35～0.55 0.05～0.15

By comparing the Chemical Composition of Hot work Alloy Tool Steel AISI H13 and SKT4,  We can know some H13 and SKT4 Chemical properties and physical properties have what different point.

1, Carbon Composition (%)

The carbon content in the steel increases, the yield point and the tensile strength increase, but the plasticity and impact are reduced. When the carbon content is over 0.23%, the welding performance of the steel is deteriorated, so the low alloy structural steel used for welding,

The amount is generally not more than 0.20%. High carbon content also reduces the atmospheric corrosion resistance of steel, high-carbon steel in the open field is easy to rust; In addition, carbon can increase the cold brittleness and aging sensitivity of steel.  SKT4’s carbon composition higher about 0.15 than H13.

 

2, silicon Composition (%)

 

Silicon is added as a reducing agent and deoxidizer during the steelmaking process, so the killed steel contains 0.15-0.30% silicon. If the silicon content of steel exceeds 0.50-0.60%, silicon even alloying elements. Silicon can significantly improve the elastic limit of steel, yield point and tensile strength, it is widely used for spring steel. In the quenched and tempered structural steel by adding 1.0-1.2% of the silicon, the strength can be increased by 15-20%. SKT4’s Sillicon composition lower about 0.70 than H13.

 

3, manganese Composition (%)

 

In the process of steelmaking, manganese is a good deoxidizer and desulfurization agent, the general steel containing 0.30-0.50% manganese. When adding more than 0.70% of carbon steel, it will not only have sufficient toughness, but also have high strength and hardness, improve the quenching of steel and improve the hot working performance of steel even if it is “manganese steel” Such as 16Mn steel than A3 yield point 40% higher. Containing 11-14% of the steel has a high wear resistance, for the excavator bucket, ball mill liner. Manganese increased, reducing the corrosion resistance of steel, reducing welding performance. SKT4’s manganese composition higher about 0.4 than H13.

 

4, Chrome Composition (%)

 

In structural steel and tool steel, chromium can significantly improve strength, hardness and wear resistance, but at the same time reduce the plasticity and toughness. Chromium can improve the oxidation resistance and corrosion resistance of steel, which is an important alloy of stainless steel, heat-resistant steel. SKT4’s Chrome composition lower about 4.0 than H13.

 

5, Molybdenum Composition (%)

 

Molybdenum can refine the grain of steel, improve the hardenability and thermal strength, at high temperatures to maintain sufficient strength and creep resistance (long-term stress at high temperatures, deformation, said creep). Structural steel by adding molybdenum, can improve the mechanical properties. It is also possible to suppress the brittleness of the alloy steel due to the fire. In the tool steel can improve the redness. SKT4’s Molubdenum composition lower about 0.75 than H13.

 

6, Vanadium Composition (%)

 

Vanadium is an excellent deoxidizer for steel. Adding 0.5% vanadium to the steel can refine the grain and improve the strength and toughness. Vanadium and carbon carbide, in high temperature and high pressure can improve the ability of hydrogen corrosion. SKT4’s Vanadium composition lower about 0.75 than H13.

H13 steel hardness can reached 58 HRc. But SKT4 only Can reached 40 HRc.

By the comparing, We can know H13 steel have higher hardness and Hot hardness, but H13 produce cost high a lot than SKT4. So some large size Hot forging mould should use H13 steel.  But some small size and lower hardness hot forging products can use JIS SKT4 Steel. So that reduce the products cost.