CN103805890A - Heat treatment process of high speed steel for cutting tool - Google Patents

Abstract

The invention discloses a heat treatment process of high speed steel for a cutting tool. The heat treatment process comprises the following steps: (1) heating in stages, to be more specific, in the first stage, heating to the temperature of 550-560 DEG C with the holding time of 20-30 minutes; in the second stage, heating to the temperature of 820-840 DEG C with the holding time of 30-40 minutes, in the third stage, heating to quenching temperature of 1070-1090 DEG C with the holding time of 60-90 minutes; (2) quenching by oil cooling; (3) tempering with the tempering temperature of 505-515 DEG C with the holding time of 90-120 minutes, then cooling by air to room temperature; and performing the tempering treatment for two times by the process.

Description

The thermal treatment process of rapid steel for a kind of cutting tool

Technical field

The present invention relates to technical field of ferrous metallurgy, relate in particular to the thermal treatment process of a kind of cutting tool rapid steel.

Background technology

Cutting tool high speed steel material is general adopts domestic high speed steel W 6Mo5Cr4V2 to make, the chemical composition of alloy is (% by weight): C0.80%～0.90%, Si≤0.45%, Mn≤0.40%, W5.50%～6.75%, Mo4.50%～5.50%, Cr3.80%～4.40%, V1.75%～2.20%, S≤0.03%, P≤0.03%, all the other are Fe.This rapid steel contains the Mo than high level, now because Mo on world market lacks, and price comparison costliness, and also this rapid steel tungsten, content of vanadium are also higher, and the cost of therefore producing alloy also raises greatly.

Chinese invention patent (notification number is CN1014081) discloses low alloy high speed steel, the specific chemical composition that it is characterized in that this steel grade is (% by weight) C0.85%～1.05%, W3.0%～5.0%, Mo2.0%～3.5%, Cr3.5%～5.0%, V1.20%～1.80%, Si0.70%～1.20%, Mn0.20%～0.50%, N0.02%-0.08%, S≤0.03%, P≤0.03%, all the other are Fe.Thereby this rapid steel reduces production costs by reducing alloying element amount, but because this rapid steel is the same with W6Mo5Cr4V2 steel, all contains than the Mo of high level, W, V, so production cost does not fundamentally obtain and reduces.

Chinese invention patent (notification number is CN1149298) discloses a kind of high-speed antiwear cast steel, the specific chemical composition that it is characterized in that this steel grade is (% by weight), C1.8%～4.2%, W2%～12%, Mo3%～12%, Cr4%～15%, Co0%～10%, V2.5%～10%, Nb0.3%～2.5%, Si0.5%～1.5%, Mn0.3%～0.8%, Al0.02%～0.10%, N0.02%～0.10%, S≤0.03%, P≤0.03%, all the other are Fe.The feature of this rapid steel is high-carbon, high vanadium, Gao Ge, adds a large amount of W, Mo, Cr, V and Nb carbide forming element, and these carbide elements are to provide the important factor of wear resistance, and therefore this rapid steel has good castability, wear-resisting.But because this rapid steel contains a large amount of Mo, V, therefore production cost is especially higher than W6Mo5Cr4V2 rapid steel, and its versatility is not strong yet.

Summary of the invention

The object of the invention is to propose the thermal treatment process of a kind of cutting tool rapid steel, this steel has obtained good hardness, wear resistance and obdurability by the adjustment of alloy constituent content, particularly after thermal treatment, performance is more excellent, and precious alloy constituent content is few, and cost is low.

For reaching this object, the present invention by the following technical solutions:

A thermal treatment process for rapid steel for cutting tool, the chemical composition of this rapid steel is made up of following component by weight percentage: C:1.2-1.4, Si:0.5-0.7, Mn:1.0-1.2, Cr:7.5-8.5, W:2.0-2.2, Mo:3.2-3.4, V:2.8-3.0, Ni:0.6-0.8, Ti:0.2-0.4, B:0.005-0.007, N:0.06-0.08, S≤0.015, P≤0.015; Surplus is iron Fe and inevitable impurity; Described thermal treatment process comprises the steps:

(1) heating stage by stage, first stage Heating temperature is to 550-560 ℃, and soaking time is 20-30 minute; Subordinate phase is heated to 820-840 ℃, soaking time 30-40 minute, and the phase III is heated to quenching temperature 1070-1090 ℃, and soaking time is 60-90 minute;

(2) quench, adopt oil cooling;

(3) tempering, tempering temperature is 505-515 ℃, and soaking time is 90-120 minute, and then air cooling is to room temperature; Carry out double tempering processing by this technique.

The effect of main alloy element of the present invention is as follows:

Carbon, the various carbide that it and carbide forming element form are vital tissue factors that steel obtains hot strength.Appropriate excess carbon compound can stop grain growth, improves wear resistance.But carbon content is too high, can make steel lose plasticity, in addition because carbide is too much, skewness, also can cause that cutter bursts apart.Silicon, its objective is the hardening capacity, temper resistance and the matrix strength that improve steel, guarantees hot strength, hot hardness and the thermostability of steel.

Manganese, its objective is the intensity that steel is provided, and can slacken and eliminate the detrimentally affect of sulphur, improves the hardening capacity of steel.Chromium, Main Function is hardening capacity, wear resistance and the oxidation-resistance that improves steel, chromium is a kind of strong carbide forming element, it can form multiple compounds with carbon, and form compound compound with iron carbon, improve hardness and the intensity of steel, and chromium and tungsten form double carbide jointly, chromium can improve double carbide solubleness in austenite in the time that temperature is lower, and can also stop high temperature time, carbide gathers.

Vanadium and nitrogen, the two forms compound, substitute expensive cobalt element, improve the red hardness of steel, vanadium can also refinement steel grain structure, improve hot hardness and the hot strength of steel, toughness and wear resistance, when it can increase the hardening capacity of steel in the time that high temperature fuses into austenite, can prevent the thermo-responsive tendency of mistake of steel.

Tungsten, Main Function is red hardness and the heat resistance that can improve steel, and can improve the wear resistance of steel.

Molybdenum, Main Function is hardening capacity and the heat resistance that can improve steel, prevents temper brittleness.

Nickel, is non-carbide forming element, improves the intensity of steel by solution strengthening mode, and plasticity, toughness are also improved.Meanwhile, add nickel can reduce the critical quenching rate of steel, thereby the hardening capacity of steel is improved greatly.

Boron, is used for improving hardness and the wear resistance of steel.

Titanium, can improve wear resisting property.

Beneficial effect of the present invention is:

High speed steel material of the present invention, compared with domestic high speed steel W 6Mo5Cr4V2, has replaced a large amount of molybdenums with chromium, has saved the usage quantity of molybdenum, and with the cobalt of the combination replacement costliness of V and N, thereby has reduced the production cost of steel alloy; Add non-carbide elemental nickel, improve the intensity of steel by solution strengthening mode, there is again high plasticity and toughness simultaneously, and the hardening capacity of steel is increased strongly, add B and Ti to improve hardness and the wear resisting property of steel.The present invention is containing P, S amount very low (particularly P), and therefore the purity of steel is good especially, and the properties of steel is played to guarantee effect.This rapid steel annealing Brinell hardness reaches HB270.Therefore rapid steel of the present invention has higher thermohardening and cutting ability, has again high toughness, wear resistance.And material cost is significantly less than domestic high speed steel W 6Mo5Cr4V2, be applicable to make cutting tool.

Embodiment

Embodiment mono-

A thermal treatment process for rapid steel for cutting tool, the chemical composition of this rapid steel is made up of following component by weight percentage: C:1.2, Si:0.7, Mn:1.0, Cr:8.5, W:2.0, Mo:3.4, V:2.8, Ni:0.8, Ti:0.2, B:0.007, N:0.06, S≤0.015, P≤0.015; Surplus is iron Fe and inevitable impurity; Described thermal treatment process comprises the steps:

(1) heating stage by stage, first stage Heating temperature to 550 ℃, soaking time is 30 minutes; Subordinate phase is heated to 820 ℃, soaking time 40 minutes, and the phase III is heated to 1070 ℃ of quenching temperatures, and soaking time is 90 minutes;

(2) quench, adopt oil cooling;

(3) tempering, tempering temperature is 505 ℃, and soaking time is 120 minutes, and then air cooling is to room temperature; Carry out double tempering processing by this technique.

Embodiment bis-

A thermal treatment process for rapid steel for cutting tool, the chemical composition of this rapid steel is made up of following component by weight percentage: C:1.4, Si:0.5, Mn:1.2, Cr:7.5, W:2.2, Mo:3.2, V:3.0, Ni:0.6, Ti:0.4, B:0.005, N:0.08, S≤0.015, P≤0.015; Surplus is iron Fe and inevitable impurity; Described thermal treatment process comprises the steps:

(1) heating stage by stage, first stage Heating temperature to 560 ℃, soaking time is 20 minutes; Subordinate phase is heated to 840 ℃, soaking time 30 minutes, and the phase III is heated to 1090 ℃ of quenching temperatures, and soaking time is 60 minutes;

(2) quench, adopt oil cooling;

(3) tempering, tempering temperature is 515 ℃, and soaking time is 90 minutes, and then air cooling is to room temperature; Carry out double tempering processing by this technique.

Embodiment tri-

A thermal treatment process for rapid steel for cutting tool, the chemical composition of this rapid steel is made up of following component by weight percentage: C:1.3, Si:0.6, Mn:1.1, Cr:8.0, W:2.1, Mo:3.3, V:2.9, Ni:0.7, Ti:0.3, B:0.006, N:0.07, S≤0.015, P≤0.015; Surplus is iron Fe and inevitable impurity; Described thermal treatment process comprises the steps:

(1) heating stage by stage, first stage Heating temperature to 555 ℃, soaking time is 25 minutes; Subordinate phase is heated to 830 ℃, soaking time 35 minutes, and the phase III is heated to 1080 ℃ of quenching temperatures, and soaking time is 75 minutes;

(2) quench, adopt oil cooling;

(3) tempering, tempering temperature is 510 ℃, and soaking time is 105 minutes, and then air cooling is to room temperature; Carry out double tempering processing by this technique.

Claims (1)

1. a thermal treatment process for rapid steel for cutting tool, is characterized in that, the chemical composition of this rapid steel is made up of following component by weight percentage: C:1.2-1.4, Si:0.5-0.7, Mn:1.0-1.2, Cr:7.5-8.5, W:2.0-2.2, Mo:3.2-3.4, V:2.8-3.0, Ni:0.6-0.8, Ti:0.2-0.4, B:0.005-0.007, N:0.06-0.08, S≤0.015, P≤0.015; Surplus is iron Fe and inevitable impurity; Described thermal treatment process comprises the steps:

(1) heating stage by stage, first stage Heating temperature is to 550-560 ℃, and soaking time is 20-30 minute; Subordinate phase is heated to 820-840 ℃, soaking time 30-40 minute, and the phase III is heated to quenching temperature 1070-1090 ℃, and soaking time is 60-90 minute;

(2) quench, adopt oil cooling;

(3) tempering, tempering temperature is 505-515 ℃, and soaking time is 90-120 minute, and then air cooling is to room temperature; Carry out double tempering processing by this technique.