Production control method for improving curvature of 42CrMo bar

Abstract

The invention relates to a production control method for improving the curvature of a 42CrMo bar, and the method comprises heating, rolling and cooling control procedures. A walking beam furnace is adopted in the heating procedure, and the heating procedure sequentially comprises a preheating section, a first heating section, a second heating section and a soaking section, wherein the temperatureof the preheating section ranges from 600 DEG C to 720 DEG C, the temperature of the first heating section ranges from 950 DEG C to 1,060 DEG C, the temperature of the second heating section ranges from 1,060 DEG C to 1,130 DEG C, the temperature of the soaking section ranges from 1,080 DEG C to 1,120 DEG C, and the total heating time ranges from 120 min to 180 min. The 42CrMo bar produced by themethod has better curvature index and uniform structure, the quenching cracking ratio of the 42CrMo bar is reduced in the subsequent machining process, and the machining efficiency and the percent ofpass of user products are improved.

Description

technical field [0001] The invention relates to a production control method of steel, in particular to a production control method for improving the curvature of 42CrMo rods. Background technique [0002] Because 42CrMo has high strength, toughness and fatigue properties after quenching and tempering, it is mostly used to process products such as automobiles, mechanical forgings and high-strength bolts. In recent years, with the development of the machining industry in the direction of energy saving, precision, and intelligence, machining companies have higher and higher requirements for performance indicators such as dimensional accuracy and bending of steel. During the production process, 42CrMo steel tends to form uneven supercooled structures such as bainite and martensite when air-cooled. Under the action of thermal stress and structural stress, the phenomenon of 42CrMo bending steel occurs from time to time. use has a greater impact. [0003] At present, the main tec...

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Problems solved by technology

Although the above technical measures have a certain effect on the control of the bending degree or structure of the steel, they also have the following disadvantages: (1) The straightening of the steel after rolling needs to be finished off-line with a straightening machine, and the production equipment is increased during the use process. , manpower consumption, prolonging the delivery cycle, on the other hand, the straightening process will also bring secondary defects such as straightening marks and surface stress, and for steel with serious bending, it cannot be straightened to meet product requirements; (2) through Covering the cooling bed with a heat preservation cover will prolong the heat preservation time, which is not conducive to on-line production control; (3) The measures of cutting off the line through high-temperature shears (saws) and cooling in a slow cooling pit can achieve effective control of the organization, but practice shows This technology is not conducive to the control of bar bending

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