CN100357477C

CN100357477C - Super bainite abrasion-resistant steel and its manuafcturing process

Info

Publication number: CN100357477C
Application number: CNB2005100793466A
Authority: CN
Inventors: 张福成; 王天生; 郑炀曾; 吕博
Original assignee: Yanshan University
Current assignee: Yanshan University
Priority date: 2005-07-06
Filing date: 2005-07-06
Publication date: 2007-12-26
Anticipated expiration: 2025-07-06
Also published as: CN1710134A

Abstract

The present invention discloses ultrafine bainite abrasion-resistant steel and a manufacturing process thereof, particularly high-carbon MnCrWSiAlV series low alloy steel which contains the following chemical components by wt%: 0.7 to 1.1 wt% of C, 0.5 to 3.0 wt% of Mn, 0.5 to 3.0 wt% of Cr, 0.1 to 2.0 wt% of W, 0.5 to 3.0 wt% of Si, 0.1 to 2.0 wt% of Al, 0.0 to 0.3 wt% of V, less than 0.05 wt% of S, less than 0.05 wt% of P and Fe as the rest. The heat treatment process is as follows: forged condition steel and as-cast condition steel have the same final heat treatment process, however, the forged condition steel needs to carry out a special forged heat treatment process after forging. Ultrafine bainite structure and little residual austenite structure with high-carbon content are obtained after final heat treatment is carried out to the steel to make workpieces obtain favorable integrative mechanical performance, wherein the high-rupturing capacity (HRC) of the workpieces reaches 60 to 65, the toughness reaches 40 to 80 J/cm<2>, and the service life is raised by 2 to 4 times of the present common ZGMn13 under the conditions of high stress abrasion and low stress abrasion.

Description

Ultra-fine Bainite wear-resisting steel and manufacturing process thereof

Technical field

The present invention relates to a kind of anti-low-stress and heavily stressed wearing and tearing wear resisting steel, it belongs to high-carbon low-alloy steel.

Background technology

Fields such as metallurgy, building materials, mine, military project and coal are extensive use of high-abrasive material.Divide from material composition, present widely used wear resisting steel mainly is divided into: austenite abrasion-proof steel, martensite wear-resistant steel and Bainite wear-resisting steel.The austenite abrasion-proof steel mainly is meant traditional ZGMn13 and develops the austenite abrasion-proof manganese steel of coming out thus, use after the tough processing of water, and hardness is greatly about HB150-250, and toughness is greatly about 150-300J/cm ², it mainly is suitable for heavily stressed abrasive conditions; The martensite wear-resistant steel mainly is meant the multi-element alloyed low alloy steel of low-carbon (LC), uses behind Q-tempering, and hardness is greatly about HRC45-55, and toughness is greatly about 20J/cm ²Below, it mainly is suitable for the low-stress abrasive conditions; Bainite wear-resisting steel is meant middle carbon high-silicon alloy steel, uses after corresponding bainitic transformation thermal treatment, and hardness is greatly about HRC40-50, and toughness is greatly about 30J/cm ²Below, it mainly is suitable for the low-stress abrasive conditions.

In this three classes wear resisting steel, Bainite wear-resisting steel is the wear resisting steel series that develops at last.The chemical ingredients of present normally used bainitic steel is C0.4-0.7, Si1.0-3.0, Mn1.0-3.0, just so-called Si-Mn is a bainitic steel, in order further to increase the hardness and the wear resisting property of steel, can utilize elements such as Cr, B, Mo to carry out Alloying Treatment again.Usually the thermal treatment process that adopts be air cooling or after being quenched into bainite transformation temperature isothermal air cooling.The bainite that so obtains is generally common carbide-free Bainite tissue, has certain martensite and residual austenite simultaneously.

Under usual conditions, under the enough precondition of toughness, high more its wear resistance of the hardness of steel is good more.Yet, the hardness of material and toughness are two contradictory elements, the hardness of steel improves certainly will reduce its toughness, on the contrary, the toughness that improves steel necessarily reduces its hardness, therefore, improving the hardness of high-abrasive material and the difficult point that toughness is Materials science simultaneously, also is one of target of Materials science worker pursuit.In order to realize this goal, except will to the chemical ingredients of steel carry out well-designed, also to utilize special modern thermal treatment process that steel is carried out unconventional thermal treatment, thereby obtain unconventional weave construction, to obtain excellent comprehensive mechanical properties.

Summary of the invention

The invention provides a kind of ultra-fine Bainite wear-resisting steel and manufacturing process thereof, it is a kind of high-carbon diversification low alloy steel.Adopt special thermal treatment process to make steel obtain the residual austenite heterogeneous structure of the ultra-fine bainite of carbides-free and a small amount of high-carbon content, thereby make steel obtain excellent comprehensive mechanical properties, hardness is equivalent to quenched martensite (HRC60-65), and toughness is equivalent to normalizing perlite (40-80J/cm ²).Under heavily stressed and low-stress abrasive conditions, improve 1-3 doubly than the common ZGMn13 steel that uses at present its work-ing life.

The technical solution adopted for the present invention to solve the technical problems is: the chemical ingredients of ultra-fine Bainite wear-resisting steel is wt%:C0.7-1.1, Mn0.5-3.0, Cr0.5-3.0, W0.1-2.0, Si1.0-3.0, Al0.1-2.0, V0.05-0.3, S＜0.05, P＜0.05, all the other are Fe; The manufacturing process of ultra-fine Bainite wear-resisting steel is: adopt electrosmelting, be cast as bar then and use after forging, perhaps directly be cast as needed part shape.Smelting tapping temperature is 1520-1550 ℃, and teeming temperature is 1460-1480 ℃; During smelting, alloying element (corresponding iron alloy) addition sequence is: ferrotungsten, ferrosilicon, ferrochrome, ferromanganese and commercial-purity aluminium, cast then.Can reduce the scaling loss of alloying element in fusion process guaranteeing that alloying element fully melts and spreads under the uniform prerequisite so as far as possible.

For forging the ultra-fine Bainite wear-resisting steel that attitude is used, the generation and the tissue heredity of white point in the steel, it forges postheat treatment technology: directly be put into when high temperature in 350 ℃ of stoves after forging and be incubated 1 hour, be incubated 2 hours after being heated to 650 ℃ of sammings then, be heated rapidly to the tissue heredity that insulation behind 880 ℃ of sammings destroyed steel in 1 hour again, be cooled to isothermal annealing behind 650 ℃ of sammings again, every 100mm cross section insulation 5 hours is handled with further expansion hydrogen, after stove is as cold as 400 ℃, air cooling.Final thermal treatment process for the steel of forging the use of attitude or as cast condition is, at first steel is heated to 800-950 ℃ and carries out the austenitizing processing, be cooled fast to above 10-100 ℃ of long-time insulation of Ms point temperature of steel then, soaking time 5-500 hour, last air cooling.Can obtain size like this at the tens ultra-fine bainite structures to the hundreds of nanometer, this bainite belongs to carbide-free Bainite.

The present invention is optimized in the chemical ingredients to steel on the basis of design, determines the chemical ingredients scope of best high-carbon low-alloy bainitic steel.At first measured the gentle continuous cooling transformation curve such as grade of steel, thereby determined the forging postheat treatment technology of steel, and steel obtains the final special thermal treatment technology of ultrafine crystal bainite tissue.The phase composite in the steel after the thermal treatment that utilized X-ray analysis, the microtexture of steel of having utilized transmission electron microscope and metallography microscope sem observation.Having tested on the conventional mechanical property bases such as the stretching of steel after the thermal treatment, impact and hardness, utilize grain-abrasion testing machine, under heavily stressed and low-stress abrasive conditions, carry out abrasive grain wear test respectively.

Forge the ultra-fine Bainite wear-resisting steel of attitude and can be used for heavily stressed wearing partss such as anti-cavitation wear, also can be used for making high strength bolt.The ultra-fine Bainite wear-resisting steel of as cast condition is used for the widely used wear parts of industry such as metallurgy, mine, building materials and coal, as liner plate, Chui head and tooth plate or the like.

The invention has the beneficial effects as follows: ultra-fine Bainite wear-resisting steel obtains the residual austenite tissue of ultra-fine bainite structure and a small amount of high-carbon content after final thermal treatment, thereby make workpiece obtain excellent comprehensive mechanical properties, hardness reaches HRC60-65, and toughness reaches 40-80J/cm ²Under heavily stressed and low-stress abrasive conditions, improve 1-3 doubly than at present widely used common ZGMn13 steel its work-ing life.

Embodiment

The abrasion-proof backing block that uses in the harbour coal handling system that utilizes the present invention to produce, its concrete chemical ingredients is wt%:C0.90, Mn2.48, Si1.42, Cr0.76, W0.51, Al0.21, V0.10, S0.018, P0.035, all the other are Fe.The Ms temperature of this steel is 198 ℃.Its thermal treatment process is, 900 ℃ of insulations are quenched into temperature after 3 hours be in 250 ℃ the salt made from earth containing a comparatively high percentage of sodium chloride, insulation 24 hours in 250 ℃ hotblast stove then, air cooling.The hardness of steel is HRC62 after this thermal treatment, and impact toughness is 45J/cm ²This abrasion-proof backing block is applied in the coal handling system of PORT OF QINHUANGDAO, and improve 2.5 times than common high manganese steel lining plate its work-ing life, receives good result of use.

Obtain that hardness is equivalent to quenched martensite and toughness is equivalent to the pearlitic excellent comprehensive mechanical properties of normalizing through special thermal treatment process.This ultra-fine Bainite wear-resisting steel can be used for making component such as anti-cavitation wear and abrasive wear, also can be used for making high strength bolt etc.

Claims

1. ultra-fine Bainite wear-resisting steel, it is characterized in that: the chemical ingredients of steel is wt%:C 0.7-1.1, Mn 0.5-3.0, Cr 0.5-3.0, W 0.1-2.0, Si 1.0-3.0, Al 0.1-2.0, V 0.05-0.3, S＜0.05, P＜0.05, all the other are Fe.

2. the manufacturing process of the described ultra-fine Bainite wear-resisting steel of claim 1 is characterized in that:

A. electrosmelting, smelting tapping temperature is 1520-1550 ℃, is cast as needed part shape then, teeming temperature is 1460-1480 ℃; During smelting, the addition sequence of alloying element is: ferrotungsten, ferrosilicon, ferrochrome, ferromanganese and commercial-purity aluminium, cast then;

B. for forging the ultra-fine Bainite wear-resisting steel that attitude is used, when high temperature, directly be put in 350 ℃ of stoves after forging and be incubated 1 hour behind the samming, be incubated 2 hours after being heated to 650 ℃ of sammings then, insulation is 1 hour behind reheat to the 880 ℃ samming, the every 100mm thick section of isothermal annealing is incubated 5 hours after being cooled to 650 ℃ of sammings again, after stove is as cold as 400 ℃, air cooling;

C. the final thermal treatment process of ultra-fine Bainite wear-resisting steel is: at first above-mentioned forging attitude and as cast condition steel are heated to 800-950 ℃ and carry out austenitizing and handle, be cooled fast to above 10-100 ℃ of long-time insulation of Ms point temperature of steel then, soaking time 5-500 hour, last air cooling.