Hot forging dies are mainly used to manufacture dies for pressure processing of workpieces under high temperature conditions, such as hot forging dies, hot extrusion dies, die-casting dies, hot upsetting dies, etc. The commonly used hot work die materials are alloy die steels with medium and high carbon content and alloy elements such as chromium, tungsten, molybdenum and barium. Hot forging dies with special requirements are sometimes made of high alloy austenitic heat-resistant die steel, high-temperature alloy and refractory alloy.

The dies used in hot forging undergo severe thermal cycle and mechanical loading. This in turn affects the life of the die, as the die is open to:

Gross Cracking

Plastic Deformation

Thermal Fatigue Cracking

Wear

forging die of connecting rod- China Yida Forging

Depending on the type of forging operation used, the material and the size of the part to be formed, forging dies are required to have the following characteristics:

A sufficient hardness as well as the ability to retain this hardness at elevated temperatures.

An sufficient hardenability as well as a resistance to fatigue.

A good ductility and toughness in all directions at both elevated and low temperatures.

Enhanced levels of both hot hardness and hot tensile strength.

The China national standard GB 1299-85 technical conditions for alloy tool steels includes 12 hot work forging die steel grades, which are mainly divided into three categories: "one is the old steel used, such as 5CrMnMo, 5CrNiMo, 3Cr2W8V, etc.; the other is the new steel developed in China, such as 5cr4mo3simova1, 3cr3mo3w2v, 5cr4w5mo2v, 4Cr5MoSiV, etc.; the other is the introduction of foreign general steel grades, such as 4Cr5MoSiV (H11), 4Cr5MoSiV1 (H13), 4cr5w2vsi (W2) Etc.