CN104178691A - High-strength steel for metallurgical saw blades and heat treatment method thereof - Google Patents

Abstract

The invention relates to a high-strength steel for metallurgical saw blades and a heat treatment method thereof, belonging to the technical field of medium-carbon low-alloy steel. The steel for metallurgical saw blades comprises the following chemical components: 0.30-0.60% of C, 0.15-0.30% of Si, 1.35-1.9% of Mn, at most 0.02% of P, at most 0.005% of S, 0.07-0.19% of V, 0.025-0.055% of Al, and the balance of Fe and inevitable impurities. The heat treatment method comprises the following steps: smelting, carrying out continuous casting, carrying out hot rolling to obtain a plate, quenching the plate, and carrying out tempering heat treatment to obtain the steel for metallurgical saw blades. By utilizing the off-line or on-line quenching+tempering heat treatment technique and using water as the quenching medium, the method has the characteristics of low cost, favorable hardenability, high efficiency, uniform hardness and the like, and is beneficial to environmental protection; and by matching with the appropriate chemical component design, the method can ensure the requirements for high hardness and high toughness, simplifies the production technique of the saw blade, shortens the production process and lowers the energy consumption.

Description

Steel and heat treating method thereof for a kind of high-strength metallurgical saw blade

Technical field

The invention belongs to medium carbon low alloy steel technical field, relate in particular to steel and heat treating method thereof for a kind of high-strength metallurgical saw blade.

Background technology

China's development of iron & steel industry is rapid in recent years, steel products great variety of goods, and in the middle of the kind of steel products, the most conventional have tubing, bar, section bar, wire rod and a strip product.In the production process of tube, rod section material, roll formed shape (deep processed product of Strip), all to use metallurgical saw to carry out cutting on line, complete the processing requirement of the tail of decaptitating, scale.Metallurgy industry is all generally large quantities of continuous production, and production efficiency, turnout are all very high, so the saw blade that metallurgy industry is used is required to meet the requirement that on-line continuous is produced, and application quantity is maximum is exactly metal cold, fervent saw blade.

Domestic production metallurgical saw mainly be take 65Mn as main with steel, and this hardness of steel is high, good rigidly, but its plasticity and toughness are poor, in saw blade production process, easily crack, and is difficult for smoothing, often there will be saw blade crackle, collapses tooth, sticks with paste the phenomenons such as tooth in use procedure.External employing 45Mn2V, 30CrMo etc. are starting material, suitably reduce carbon content, add the elements such as microalloy vanadium, chromium, molybdenum, improved the temper resistance of steel, security deposit's phase constitution changes completely and is even, tempering rear panel body stress is evenly distributed, easily adjustment, in mechanical property, not only tensile strength is high, and good toughness, during sawing, be out of shape littlely, be improved largely work-ing life than 65Mn.

The mode of production of saw blade is mainly at present: steel mill is responsible for carrying out the rolling of steel for saw blade, and hot-rolled state is paid saw blade manufacturer, and manufacturer, through being machined into wafer body, then carries out modified thermal treatment.Matrix quenching heat treatment generally adopts air furnace preheating, the heating of ordinary salt liquid furnace, puts into rapidly oil groove or saw blade injector surface is quenched after insulation.The main drawback that cannot overcome while adopting oil quenching has: the oil smoke severe contamination air producing while, using oil quenching, is unfavorable for environmental protection and operator's health; Two, tempering oil can be aging after life-time service, needs periodic replacement, and cost is higher; Three, compare with using water quenching, the efficiency of oil quenching is low, cost is high and uniformity of hardness is low; Four, easily catching fire is the potential safety hazard of oil maximum when quenching.

For improving the manufacturability of steel saw blade and the toughness after modified thermal treatment, when guaranteeing the intensity of steel saw blade, develop as much as possible the steel grade that carbon content is low.Working environment while improving saw blade quenching, improves the production efficiency of saw blade, the cost of reduction saw blade quenching heat treatment, is the target that saw blade manufacturer is pursued always.

Publication number is that the Chinese invention patent of CN1241645A has openly illustrated matrix steel for diamond sawblade and manufacture method thereof, it is alloy designs that this matrix steel for diamond sawblade adopts C-Cr-Mo-Si-Mn, C:0.2～0.3%, Cr:1.0～1.5%, Mo:0.2～0.5%, Mn:0.65～1.3%, Si:0.15～0.30%; Sheet material thermal treatment comprises anneal, quench treatment and temper; Quench treatment temperature is 820～890, and ℃ Quenching Soaking Time 0.3～3 hour is carried out oil quenching after insulation.This steel is applied to the production of diamond saw blade substrate; In chemical composition, carbon content is low, but adds more Cr alloy and the noble metal elements Mo alloy of content, and cost is higher; Quenching mode is still oil quenching, polluted air, and low compared with shrend efficiency, cost is high.

Grant number is the chemical composition that the Chinese invention patent of CN1166801C has openly illustrated diamond body steel, and this steel is designated as 50Mn2VAl steel, and is applied to the production of diamond saw blade substrate; It is alloy designs that chemical composition adopts C-Si-Mn-V-Al, C:0.35～0.65%, Si:0.1～0.35%, Mn:1.3～2.0%, V:0.06～0.20%, Al:0.02～0.06%; After smelting, ingot casting, be rolled into sheet material, become the blank of diamond saw blade substrate, matrix blank, after quenching, tempering heat treatment, becomes diamond saw blade substrate.This steel quenching heat treatment medium is machine oil, is unfavorable for environmental protection and workers ' health.

Summary of the invention

The object of the present invention is to provide steel and heat treating method thereof for a kind of high-strength metallurgical saw blade, the method has overcome the shortcomings such as the environmental pollution, the cost that bring at traditional oil quenching are high, efficiency is low, hardness is inhomogeneous, there is the features such as cost is low, hardening capacity good, efficiency is high, hardness is even, coordinate suitable chemical composition design, make its requirement that can guarantee high rigidity, high tenacity, can simplify again production technique, shortening Production Flow Chart, the reduction energy consumption of saw blade.

The chemical composition design of steel for metallurgical saw provided by the invention, the chemical composition that specifically comprises following weight percentage forms: C 0.30～0.60%, Si 0.15～0.30%, Mn 1.35～1.9%, P≤0.02%, S≤0.005%, V0.07～0.19%, Al 0.025～0.055%, and all the other are iron Fe and inevitable residual element and impurity.

In the present invention, continuous casting material chemical composition is preferably by weight percentage: C 0.4～0.5%, Mn1.35～1.55%, P≤0.015%, S≤0.003%, Al 0.03～0.04%, V 0.07～0.10%, and all the other are iron Fe and inevitable residual element and impurity.

Chemical composition design of the present invention is described as follows:

C: be the important element that guarantees quenching hardness and hardening capacity, compare with 65Mn, reduce carbon content, when guaranteeing quenching hardness, improve the toughness of steel, reduce the tendency of thermal treatment cracking, reduce decarburizing tendency simultaneously.

Si: as reductor, while surpassing 0.5%, can cause the toughness of steel to decline in steelmaking process.

Mn: manganese with low cost, can increase toughness, intensity and the hardness of steel, be the element of strong stable austenite, can effectively reduce austenitic decomposition rate, improve the hardening capacity of steel.

P≤0.02%, S≤0.005%: in the ordinary course of things, p and s is all harmful element in steel, the fragility of increase steel.Therefore should reduce the content of p and s in steel, to reduce the formation of segregation and sulfide inclusion as far as possible.

V: vanadium can improve hardening capacity and the red hardness of steel has increased the thermostability of steel simultaneously.VC, VN particle that vanadium and C, N form are the wear-resisting particles that hardness is higher, improve the wear resistance of steel.The content of vanadium is too high, can significantly increase cost.

Al: aluminium is reductor conventional in steel, adds a small amount of aluminium in steel, can crystal grain thinning, improve impelling strength.Aluminium also has oxidation-resistance and corrosion resistance, and aluminium and chromium, silicon share, and can significantly improve the high temperature non-scale performance of steel and the ability of high-temperature corrosion resistance, too high hot workability and the machinability that affects steel.

The heat treating regime of Heat Treatment Of Steel process using press quenching or off-line quenching+tempering for metallurgical saw of the present invention.

Press quenching technique: utilize UFC (supper-fast cooling)+ACC (accelerated stream the is cooling) type of cooling to realize steel plate press quenching, cooling zone mean rate is not less than 20 ℃/S, quenches and stops when temperature is down to 200～300 ℃;

Off-line quenching technology: quenching temperature is 800～900 ℃, soaking time is 10～45 minutes, and quenchant is water, and the roller speed of quenching press is 20～35m/s.

Tempering process: tempering temperature is 500～600 ℃, soaking time is 4～12 hours, the laggard line space of tempering is cold.

The high-strength metallurgical steel saw blade that the present invention produces, steel plate yield strength Rp after quenching _0.2>=1300MPa, tensile strength Rm>=1400MPa, unit elongation A ₅₀>=15%, 20 ℃ of impact toughness value A _k>=30J, surface hardness is HRC60 ± 2; Steel plate yield strength Rp after tempering _0.2>=1100MPa, tensile strength Rm>=1200MPa, unit elongation A ₅₀>=20%, 20 ℃ of impact toughness value A _k>=70J, surface hardness is HRC 28～40; .

Tool of the present invention has the following advantages:

1) suitably reduce carbon content, after thermal treatment, steel plate, having suitable intensity and hardness simultaneously, also has higher obdurability and thermostability, excellent combination property.

2) adopt online or off-line quenching heat treatment technique, there is the features such as cost is low, hardening capacity good, efficiency is high, hardness is even, improved production efficiency simultaneously, saved the energy.

3) utilize water medium to quench, Working environment when greatly improving saw blade and quenching, is beneficial to the protection of operator's healthy and environment, and prevents the generation of the Peril Incident such as on fire.

Accompanying drawing explanation

Accompanying drawing 1 is the metallographic structure figure after quenching

Accompanying drawing 2 is the metallographic structure figure after tempering

Embodiment

Adopt chemical composition of the present invention and production method, produced 3 stoves (3 batches) metallurgical saw steel.The chemical composition of 3 stove steel is as shown in table 1.3 stove steel processes are smelted, continuous casting, and are rolled into 15mm specification heavy-gauge sheeting, then heat-treat, and heat treatment process parameter is as shown in table 2.After thermal treatment, every batch of steel plate is sampled, sample is carried out to mechanical property detection, detected result is as shown in table 3.

The chemical composition (% by weight) of table 1 embodiment steel, surplus is Fe

The heat treatment parameter of table 2 embodiment steel plate

Mechanical property after table 3 embodiment steel plate hot is processed

Note: in table, data are the mean value of a plurality of samples.

Claims (3)

1. a high-strength metallurgical saw blade steel, it is characterized in that, chemical component weight percentage ratio is: C 0.30～0.60%, Si 0.15～0.30%, and Mn 1.35～1.9%, P≤0.02%, S≤0.005%, V0.07～0.19%, Al 0.025～0.055%, and all the other are Fe and inevitable residual element and impurity.

2. metallurgical saw steel according to claim 1, is characterized in that, chemical component weight percentage ratio is: C 0.4～0.5%, and Mn 1.35～1.55%, P≤0.015%, and S≤0.003%, Al0.03～0.04%, V 0.07～0.10%.

3. a high-strength metallurgical saw blade Heat Treatment Of Steel method described in claim or 2, is characterized in that, quenchant is water, takes off-line or press quenching+tempering heat treatment process;

Press quenching technique: utilize the UFC+ACC type of cooling to realize steel plate press quenching, cooling zone mean rate is not less than 20 ℃/S, quenches and stops when temperature is down to 200～300 ℃;

Off-line quenching technology: quenching temperature is 800～900 ℃, soaking time is 10～45 minutes, and quenchant is water, and the roller speed of quenching press is 20～35m/s;

Tempering process: tempering temperature is 500～600 ℃, soaking time is 4～12 hours, the laggard line space of tempering is cold.