Hot working method of die steel large-scale modular forgings

Abstract

The invention is a mould steel large-scale module cast thermal processing method, and its character: adopting 'four-fire forging method', namely a 'pagoda sizing, heavily pressing of head and tail, first flat and later wide and wave forging in segments' forging molding mode: (1) heating with fire and pressing the steel ingot head into handle; (2) heating with fire and stamping and deforming; (3) heating with fire, making 'pagoda sizing' on the stamped blank; lightly pressing the surface of the steel blank, taking two surfaces with larger temperature difference as flat surfaces, forging and pressing at a large pressing quantity; when the tail has inner concave part in the center, forging the middle: 'heavily pressing of head and tail' to make the forged piece change into a medium blank with tail and head salient externally; 'first flat and later wide and wave forging in segments' to forge the medium blank into semi-finished product with wave; turning about the forge piece and forging into smooth finished product. It has simple technique, low making cost, good quality of forge piece and increases the yield by not less than 2.5%.

Description

Technical field [0001] The invention relates to a hot working forming method of die steel in the metallurgical industry, in particular to a hot working forming method of a die steel modular forging. Background technique [0002] Die steel is a special alloy steel, generally divided into three categories: cold work die steel, hot work die steel and plastic mold steel. Hot work die steel is mainly used to make molds for hot working of metal under high temperature conditions, such as hot forging die (5CrNiMo and other low-alloy hot work die steels for forging modules; 5CrNiMo die steel is a traditionally commonly used hot forging die steel, It has high toughness, good impact resistance, strong hardenability, and certain thermal fatigue resistance. It is widely used to manufacture medium and large module forgings with complex shapes, large impact loads, and high strength and toughness requirements), hot extrusion Molds, die-casting molds, hot shearing molds, etc. Plastic mold steel i...

AI Technical Summary

Problems solved by technology

The disadvantage of this forging process is that when the forging billet is drawn to the middle billet, due to the large cross-section of the forging billet, the deformation and penetration are difficult, so that the center of the forging billet head and tail is concave, resulting in a low billet forming rate of the steel ingot, and the module is qualified. The yield is only 66.93% (the hydrogen content in the steel ingot is less than 1.50ppm; the hydrogen content in the steel ingot is also an important factor affecting the module yield, the higher the hydrogen content, the lower the module pass rate)

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