Hot Forging Steel Temperature Range

The forging temperature range refers to the temperature interval between the forging start temperature (initial forging temperature or opening forging temperature) and the forging temperature (final forging temperature or stop forging temperature).

The initial forging temperature is mainly limited by overheating and overburning. For carbon structural steel, the initial forging temperature gradually decreases with the increase of carbon content; while the initial forging temperature of alloy tool steel should be greatly reduced with the increase of carbon content. Forgers often call whether steel has good heating performance as "hot" and "not hot". For example, low-carbon steel can be heated above 1200℃, which is called “hot-hot”; high-carbon steel is generally heated to below 1200℃. Called not to eat fire. The degree of fire eating of steel has the closest relationship with carbon content (low carbon steel eats fire best; the higher the carbon content in steel, the worse it eats fire). Generally, experienced blacksmiths use low-carbon steel as the standard, and set it to eat 12% of the fire, 35 steel is next to low-carbon steel, 90%, and 55, 60, 60Mn steel 80%. Fire, 65Mn, 70 steel eats 70% fire; carbon tool steel eats 60% fire, in order to control the fire size of the forging.

The final forging temperature should mainly ensure that the metal blank is still in an easily deformed state before stopping forging. Stopping the forging prematurely above the final forging temperature is also very disadvantageous, with the following disadvantages:

1) It is necessary to increase the number of heating, thereby increasing the consumption of metal and fuel.

2) Reduced productivity.

3) Lead to coarse grains.

The final forging temperature is generally determined by the carbon content of the steel. For steels with a carbon mass fraction of less than 0.80% (called hypoeutectoid steel, such as 45 steel), the final forging temperature should generally be around 800°C; for carbon quality For steels with a fluorescence fraction greater than 0.80% (referred to as hypereutectoid steels, such as T10, T12, etc.), the final forging temperature should generally be around 750 ~ 800 ℃ to facilitate the breaking of network carbides. In the finishing process, the final forging temperature is allowed to be 50 ~ 80℃ lower than the specified temperature.

In actual production, when determining the forging temperature range of the last fire of a forging, the initial forging temperature must be determined according to the deformation of the metal. If the deformation is small and the heating temperature is still the highest initial forging temperature, the final forging temperature will be too high as a result, resulting in coarse grains in the forging. When forging is stopped at a high final forging temperature (such as 900°C), coarse grains will be obtained; if the heating temperature is chosen to be a lower initial forging temperature and forging stopped at 800°C, fine grains can be obtained.

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