H13 die steel is one of the most widely used hot die steels at home and abroad.
The commonly used smelting methods for domestic H13 steel include electric furnace smelting + electroslag remelting and electric furnace smelting + vacuum refining outside the furnace. Electroslag smelting plays an important role in controlling the cleanliness and homogeneity of H13 steel and is an important step in the production of high-quality H13 steel. Relatively speaking, electric furnace smelting costs are low, and H13 steels with lower S and P contents (≤ 0.003% S, ≤ 0.015% P) can also be produced using refining methods such as LF+VD.
The domestic production practice has proved that the H13 steel produced by electric furnace smelting is low in transverse toughness and cannot meet the NADCA#207-2003 “North American Moulding Association H13 Microstructure Rating Chart” standard. The use of electric furnace smelting in advanced foreign special steel plants can also produce H13 steel with higher transverse toughness. Therefore, there is a need to conduct comparative studies on H13 steel smelted by electroslag and electric furnace.
The microstructure and properties of H13 die steel were studied. The differences between H13 furnace steel and electroslag steel are as follows:
Due to different methods of smelting, H13 electric furnace steel is compared with electroslag steel.
1. The electric furnace steel has poor compactness and low purity;
2. Annealed band segregation is severe and the annealed microstructure is not uniform;
3. Many liquefied carbides did not change after quenching and tempering; in the impact test, where the chain liquefied carbides accumulate, they tend to crack. The transverse fringes appear on the fractures, resulting in low toughness.
H13 mold steel application:
Mainly used for hot forging die, hot extrusion die and aluminum die casting die.
Chemical composition and function of H13 die steel
H13 steel is a C-Cr-Mo-Si-V steel, grade 4Cr5MoSiV1.
The carbon (C) is 0.32 to 0.45%, the silicon (Si) is 0.80 to 1.20%, the manganese (Mn) is 0.20 to 0.50%, the chromium (Cr) is 4.75 to 5.50%, and the vanadium (V) is 0.80 to 1.20%. Molybdenum (Mo) is 1.10~1.75%, Sulfur (S) Permissible residual content is ≤ 0.030%, Phosphorus (P) Permissible residual content is ≤ 0.030
Some chemical components function as follows:
1. Increasing the carbon content in steel will increase the strength of the steel. For hot die steels, it will increase the high temperature strength, hot hardness and wear resistance, but it will lead to a decrease in the toughness. Therefore, to maintain the strength of the premise to reduce the carbon content of steel as much as possible.
2. Chromium has a favorable effect on the wear resistance, high temperature strength, hot hardness, toughness and hardenability of the steel, and its dissolution into the matrix will significantly improve the corrosion resistance of the steel.