Alloy steel and preparation method and application thereof

Abstract

The invention provides alloy steel and a preparation method and application thereof. The alloy steel comprises the following components of, in percentage by mass, 0.24-0.29% of carbon, 0.20-0.35% of silicon, 1.15-1.35% of manganese, 0-0.012% of phosphorus, 0-0.010% of sulfur, 1.35-1.45% of chromium, 0.04-0.08% of niobium, 0.10-0.18% of molybdenum, and the balance Fe and unavoidable impurities. Thepreparation method comprises the following steps: mixing the raw materials in the formula amount, smelting and casting, forging, rolling and performing heat treatment to obtain the alloy steel. According to the alloy steel provided by the invention, the content of the niobium and chromium elements is increased, the content of the molybdenum element is reduced, the cost of the alloy steel is low,and the alloy steel has the advantages of high strength and good toughness.

Description

technical field [0001] The invention belongs to the technical field of metallurgy and relates to an alloy steel and its preparation method and application. Background technique [0002] In alloy steel, in addition to iron and carbon, other alloying elements are added. It is an iron-carbon alloy formed by adding an appropriate amount of one or more alloying elements on the basis of ordinary carbon steel. According to the different elements added and appropriate processing technology, special properties such as high strength, high toughness, wear resistance, corrosion resistance, low temperature resistance, high temperature resistance, and non-magnetic properties can be obtained. [0003] Since the 1970s, the development of high-strength alloy steels worldwide has entered a new period. Based on the metallurgy of controlled rolling technology and micro-alloying, modern low-alloy high-strength steels, namely micro-alloyed steels, have been formed. new concept. [0004] In the ...

AI Technical Summary

Problems solved by technology

The steel clocks used in the general market often have factors such as large energy consumption, not environmentally friendly (such as 42MnMo7), or expensive (27CrMo45), or unstable processes (26CrMnMo)

[0006] Moreover, since the threaded part of the non-excavation drill pipe must undergo QPQ salt bath nitriding-oxidation treatment after quenching and tempering, and this process requires a certain temperature. Melting, and at the same time, the activity is also low, too high salt bath composition is easy to age, and this process temperature requires that the tempering temperature of the non-excavation drill pipe should not be lower than 580 ° C at least after quenching, otherwise the thread of the drill pipe will be nitrided The performance of the part is reduced, so that it cannot meet the standard of S135 steel grade

[0007] The tempering temperature of 42MnMo7 after quenching is just about 550°C, which is equivalent to secondary tempering after nitriding, which still has a certain degrading effect on its performance. At the same time, this material must be quenched for oil (water quenching is easy to crack), which consumes energy and causes pollution. quite serious

The tempering temperature of 27CrMo45 after quenching is about 580°C, so that the subsequent nitriding will not reduce the performance after tempering, but due to the excessive addition of Mo element (while molybdenum element is more expensive), its production cost is high

26CrMnMo is tempered at about 540°C after quenching, and the performance of the thread part is slightly reduced after salt bath nitriding, resulting in a large difference in the performance of the entire pipe body

This solution also has the problem of high cost, and the strength and toughness need to be further improved

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