阅读说明：本技术 一种解决高合金结构钢调质后低温冲击功偏低的方法 (Method for solving low-temperature impact energy of high-alloy structural steel after hardening and tempering ) 是由 马天超 陈列 董贵文 刘光辉 张立明 李艾 李庆斌 于 2020-06-18 设计创作，主要内容包括：本发明涉及一种解决高合金结构钢调质后低温冲击功偏低的方法,属于冶金技术领域。为解决高合金结构钢在调质后低温冲击功偏低的问题,本发明提供了一种解决高合金结构钢调质后低温冲击功偏低的方法,包括淬火和高温回火的调质过程,高温回火工艺为：将淬火冷却后的钢材料加热到590±5℃,均温后保温8h；然后采用水冷将钢材料冷却至50～100℃,避免第二类回火脆性,防止回火脆性导致的低温冲击功偏低,实现了高合金结构钢-40℃低温冲击功合格,缩短了产品交付周期,防止造成钢材内部损失。(The invention relates to a method for solving the problem of low-temperature impact energy of high-alloy structural steel after hardening and tempering, and belongs to the technical field of metallurgy. In order to solve the problem that the low-temperature impact energy of the high-alloy structural steel is lower after quenching and tempering, the invention provides a method for solving the problem that the low-temperature impact energy of the high-alloy structural steel is lower after quenching and tempering, which comprises the quenching and tempering processes of quenching and high-temperature tempering, wherein the high-temperature tempering process comprises the following steps: heating the steel material after quenching and cooling to 590 +/-5 ℃, and keeping the temperature for 8h after temperature equalization; and then cooling the steel material to 50-100 ℃ by water cooling, avoiding the second type of temper brittleness, preventing the low-temperature impact energy caused by the temper brittleness from being low, realizing the qualification of the low-temperature impact energy of the high-alloy structural steel at-40 ℃, shortening the delivery cycle of the product and preventing the internal loss of the steel material.)

1. A method for solving the problem that the low-temperature impact energy of high-alloy structural steel after quenching and tempering is lower comprises quenching and tempering processes of high-temperature tempering, and is characterized in that the high-temperature tempering process comprises the following steps: heating the steel material after quenching and cooling to 590 +/-5 ℃, and keeping the temperature for 8h after temperature equalization; and then cooling the steel material to 50-100 ℃ by adopting water cooling.

2. The method for solving the problem of low-temperature impact energy of the quenched and tempered high-alloy structural steel as recited in claim 1, wherein the temperature of water used for water cooling is controlled to be 15-18 ℃.

3. The method for solving the problem of low-temperature impact energy of the quenched and tempered high-alloy structural steel as recited in claim 2, wherein the high-temperature tempering is performed by using a warm charging furnace.

4. The method for solving the problem of low-temperature impact energy of the quenched and tempered high-alloy structural steel according to claim 3, wherein the quenching process comprises the following steps: heating the steel material to 650 +/-10 ℃, and preserving heat for 4 hours; heating to 930 +/-10 ℃ at a first heating rate, and keeping the temperature for 2 hours after temperature equalization; heating to 950 +/-10 ℃ at a second heating rate, and keeping the temperature for 2 hours after temperature equalization; and (3) discharging from the furnace for quenching, wherein the quenching medium is water, the cooling medium is 20# mechanical oil, and the cooling is carried out to 50-100 ℃ for 0.5 h.

5. The method for solving the problem of low-temperature impact energy of the quenched and tempered high-alloy structural steel as recited in claim 4, wherein the first temperature rise rate is controlled to be less than 60 ℃/h.

6. The method for solving the problem of low-temperature impact energy of the quenched and tempered high-alloy structural steel as recited in claim 5, wherein the second temperature rise rate is controlled to be less than 80 ℃/h.

7. The method for solving the problem of low-temperature impact energy of the quenched and tempered high-alloy structural steel according to claim 6, wherein the high-alloy structural steel comprises the following chemical components in percentage by weight: 0.45 to 0.50 percent of C, 0.40 to 0.50 percent of Si, 0.45 to 0.60 percent of Mn, less than or equal to 0.010 percent of P, less than or equal to 0.005 percent of S, 2.00 to 2.50 percent of Cr, 4.00 to 4.50 percent of Ni, 1.55 to 1.60 percent of Mo, 0.15 to 0.20 percent of V, 0.50 to 0.60 percent of W, less than or equal to 0.060 percent of Cu, less than or equal to 0.030 percent of Al, and the balance of Fe and inevitable impurities.

Technical Field

The invention belongs to the technical field of metallurgy, and particularly relates to a method for solving the problem that low-temperature impact energy of high-alloy structural steel is low after hardening and tempering.

Background

The high alloy structural steel refers to the alloy structural steel with the total content of alloy elements of more than 10%, and various special properties can be obtained by adding larger content of the alloy elements, wherein the corrosion resistance, the heat resistance and the oxidation resistance under high temperature and the high toughness under low temperature of different mediums are particularly improved.

The low-temperature impact energy is the capability of the material for resisting impact at low temperature, and reflects the toughness of the material at a certain temperature. Generally, the lower the temperature, the slower the molecular motion of the material, the relatively small intermolecular forces, and the reduced elasticity. Therefore, the lower temperature of the material still has higher low-temperature impact energy, which indicates that the material has good toughness and can be applied in more applications in low-temperature environments.

The low-temperature impact energy result of the high-alloy structural steel after quenching and tempering is usually low, and the low-temperature impact energy index requirement at the temperature of minus 40 ℃ cannot be met by quenching and tempering for multiple times or tempering for multiple times, so that the application of the high-alloy structural steel in a low-temperature environment is limited, and the delivery period and the production cost are influenced.

Disclosure of Invention

The invention provides a method for solving the problem that the low-temperature impact energy of high-alloy structural steel is low after hardening and tempering, and aims to solve the problem that the low-temperature impact energy of the high-alloy structural steel is low after hardening and tempering.

The technical scheme of the invention is as follows:

a method for solving the problem that low-temperature impact energy is low after high-alloy structural steel is quenched and tempered comprises quenching and tempering processes of quenching and high-temperature tempering, wherein the high-temperature tempering process comprises the following steps: heating the steel material after quenching and cooling to 590 +/-5 ℃, and keeping the temperature for 8h after temperature equalization; and then cooling the steel material to 50-100 ℃ by adopting water cooling.

Furthermore, the temperature of water used for water cooling is controlled to be 15-18 ℃.

Further, the high-temperature tempering adopts a warm charging furnace.

Further, the quenching process comprises the following steps: heating the steel material to 650 +/-10 ℃, and preserving heat for 4 hours; heating to 930 +/-10 ℃ at a first heating rate, and keeping the temperature for 2 hours after temperature equalization; heating to 950 +/-10 ℃ at a second heating rate, and keeping the temperature for 2 hours after temperature equalization; and (3) discharging from the furnace for quenching, wherein the quenching medium is water, the cooling medium is 20# mechanical oil, and the cooling is carried out to 50-100 ℃ for 0.5 h.

Further, the first temperature increase rate is controlled to be 60 ℃/h or less.

Further, the second temperature increase rate is controlled to 80 ℃/h or less.

Further, the high-alloy structural steel comprises the following chemical components in percentage by weight: 0.45 to 0.50 percent of C, 0.40 to 0.50 percent of Si, 0.45 to 0.60 percent of Mn, less than or equal to 0.010 percent of P, less than or equal to 0.005 percent of S, 2.00 to 2.50 percent of Cr, 4.00 to 4.50 percent of Ni, 1.55 to 1.60 percent of Mo, 0.15 to 0.20 percent of V, 0.50 to 0.60 percent of W, less than or equal to 0.060 percent of Cu, less than or equal to 0.030 percent of Al, and the balance of Fe and inevitable impurities.

The invention has the beneficial effects that:

the method for solving the problem that the low-temperature impact power of the high-alloy structural steel is low after tempering mainly controls the working procedure in the tempering process, the tempering temperature is controlled at 590 ℃, the cooling mode after tempering replaces air cooling with water cooling, the water cooling water temperature is controlled at 15-18 ℃, the steel after tempering is cooled to 50-100 ℃ with water, the second type of tempering brittleness is avoided, the low-temperature impact power caused by the tempering brittleness is prevented from being low, the qualification of the low-temperature impact power of the high-alloy structural steel at minus 40 ℃ is realized, the product delivery cycle is shortened, and the internal loss of the steel is prevented.

Detailed Description

The technical solutions of the present invention are further described below with reference to the following examples, but the present invention is not limited thereto, and any modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention. In the following examples, the processing equipment or apparatus not specifically mentioned is conventional in the art, and the technical means not specifically mentioned is conventional means well known to those skilled in the art.