Flame cutting process of medium and high carbon steel plate

Abstract

The invention discloses a flame cutting process of a medium and high carbon steel plate, and belongs to the technical field of steel plate manufacturing. The process aims at ensuring the steel plate cutting face quality. A numerical control flame cutting machine is adopted, after a steel plate to be cut is placed on the numerical control flame cutting machine, the surface of the steel plate to becut is perpendicular to a cutting nozzle of the numerical control flame cutting machine, the cutting nozzle is perpendicular to the surface of the steel plate, the height between the cutting nozzle and the surface of the steel plate is 25 to 30 mm, according to the steel plate thickness value, cutting parameters are set, the right-angle position formed through the surface of the steel plate to becut and the side face serves as the cutting point, the flame strength of the cutting nozzle is adjusted, the length of secondary flames reaches the bottom of the steel plate to be cut, before cutting,preheating is carried out at the cutting point, after the set preheating time is achieved, cutting oxygen is opened, when slag to be melted flows downwards along the edge, the cutting nozzle is movedforwards, when the slag is discharged from the bottom, the moving speed of the cutting nozzle is increased to be normal, and after the steel plate is cut, stacking for slow-cooling or high-temperature tempering is carried out. The flame cutting process is used for cutting the medium and high carbon steel plate with the thickness of 50 to 250 mm.

Description

technical field [0001] The invention belongs to the technical field of steel plate manufacturing, in particular to a flame cutting process for medium and high carbon steel plates. Background technique [0002] Medium-high carbon steel and alloy steel are prone to cracks after flame cutting and cooling to room temperature. This crack is caused by the sum of thermal stress plus tissue stress greater than the breaking strength of the material. Using optical microscope, scanning electron microscope and energy spectrum analysis to analyze the cutting cracks of steel plate, the results show that the cutting cracks of steel plate are mainly in the process of being cut by oxygen, which is equivalent to heating the steel to the critical point AC3 (When the hypoeutectoid steel is heated, all ferrite is transformed into austenite temperature) above, and the critical cooling rate is greater than V after heat preservation, then this process has actually quenched the steel, and the cuttin...

AI Technical Summary

Problems solved by technology

The extra-thick steel plate flame cutting process is a relatively advanced representative process of traditional flame cutting, but the process has an obvious defect that the steel plate after the flame cutting process is cooled to room temperature due to The cooling is relatively rapid, and it is bound to be prone to cracks, which will lead to a high rate of defective products. Therefore, it is still necessary to propose a new flame cutting process to achieve the control of the entire flame cutting process and achieve the desired purpose.