CN103233171B

CN103233171B - A kind of NM400 level cracking resistance line high-strength abrasion-proof steel and production method

Info

Publication number: CN103233171B
Application number: CN201310169373.7A
Authority: CN
Inventors: 李德发; 王世森; 熊玉彰; 董汉雄; 余宏伟; 张云燕; 熊涛; 陈勇; 洪君; 易勋
Original assignee: Wuhan Iron and Steel Group Corp
Current assignee: Baowu Group Echeng Iron and Steel Co Ltd
Priority date: 2013-05-10
Filing date: 2013-05-10
Publication date: 2015-11-18
Anticipated expiration: 2033-05-10
Also published as: CN103233171A

Abstract

A kind of NM400 level cracking resistance line high-strength abrasion-proof steel, its component and weight percent content are: C:0.04 ~ 0.08%, Si:0.20 ~ 0.50%, Mn:1.20 ~ 1.50%, P :≤0.015%, S :≤0.005%, Cr:0.25 ~ 0.60%, Mo:0.20 ~ 0.50%, Ti:0.005 ~ 0.025%, B:0.001 ~ 0.005%, Als:0.015 ~ 0.05%; Production stage: smelt also continuous casting and become base; Strand is heated; Rolling; Water cooling; Air cooling is to room temperature; Tempering.Cost of alloy of the present invention is low, alloy addition level is less, welding property and anti-flame cutting crack-sensitivity performance excellent, and avoid the energy loss that complicated thermal treatment process brings, significantly shorten the production cycle simultaneously, while there is excellent welding property and anti-flame cutting crack-sensitivity performance, because manufacturing process is simple and flow process is short, cost reduction by 15%, energy consumption reduction by 25% can be made, process operability improves, therefore there is the very strong market competitiveness and wide application prospect, economic benefit and social benefit obvious.

Description

A kind of NM400 level cracking resistance line high-strength abrasion-proof steel and production method

Technical field

The invention belongs to mechanical engineering wear resisting steel and manufacture field, particularly a kind of NM400 level cracking resistance line high-strength abrasion-proof steel and working method thereof.

Background technology

Wearing and tearing generally occur on the friction surface of material, and a large amount of statistics shows, the nearly half of the energy is consumed in wearing and tearing, and 80% of material lost efficacy in wearing and tearing, the shut-down that manpower changes component if add, and mechanical product quality difference efficiency is low, then financial loss can be larger.According to statistics, China consumes metal wear resistant material every year and about reaches more than 3,000,000 tons, and application frictional wear theory prevents and alleviates frictional wear, can save 15,000,000,000 dollars every year.Current spendable high-abrasive material is divided into the three major types such as metal and metallic compound, ceramic composite materials, plastics, and wherein metal wear resistant material still occupies dominant position.In metal wear resistant material, non-ferrous metal, Wimet and metal-base composites due to starting material and preparation cost higher, general only for parts and the special industry of particularly important, as Aeronautics and Astronautics etc.In current Practical Project application at most, consume maximum abrasion resistance of metal material still based on wear-resisting steel plate.

The wear resisting steel traditional for engineering machinery is generally high mangaenese steel, rely on the work hardening that high mangaenese steel has, be hit in its use procedure after stress and have very strong hardening capacity, so can only play its effect under large shock load, and the wear resistance of its hardness cannot improve for the little operating mode of shock load, and after high mangaenese steel work hardening, its yield strength is not high, under effect more energetically, workpiece also can produce cracking sometimes, is difficult to the work-ing life reaching expection.High mangaenese steel is mostly foundry goods, needs special thermal treatment and water patent, complex process.In recent years, low-alloy wear-resistant steel, for making middle-size and small-size mechanical material, too in engineering machinery field application, is approved by machinery industry, and is become trend, and for meeting engineering machinery large scale development trend, its intensity rank needs to be improved further.

But the problem that the wear resisting steel ubiquity cost of current all hardness number HBW/10/3000 >=400 is high, is mainly reflected in chemical composition and manufacturing process.First chemical composition all with the addition of a large amount of precious alloys; Manufacturing process aspect, generally adopt hardening and tempering process produce, energy consumption and process cost high.Therefore study a kind of high-strength abrasion-proof steel of low cost manufacturing process that adopts significant, its novelty is mainly reflected in low-alloy chemical composition design and Micro Alloying manufacturing process aspect, has not only improve intensity and wear resistance but also has significantly reduced manufacturing cost.

Through retrieval, China Patent Publication No. is the patent documentation of CN1109919A, disclose a kind of low-alloy wear-resistant steel, its composition by weight percent is: C:0.5 ~ 0.6%, Si:0.9 ~ 1.2%, Mn:1.4 ~ 1.7%, Cr:1.35 ~ 1.60%, Mo:0.3 ~ 0.5%, V:0.05 ~ 0.10%, Ti:0.03 ~ 0.06%, Re:0.02 ~ 0.04%, intensity and wear resistance are all better, but a large amount of alloying element adding raising hardening capacity, cost is higher, and C, Si content height easily produces quenching crack, adds rare earth element and disagrees with economizing on resources of advocating at present.

China Patent Publication No. is the patent documentation of CN102605272A, disclose a kind of Low-alloy ultrahigh-strength wear-resistant steel and production method thereof, die casting method is adopted to obtain ingot casting, its composition by weight percent is: C:0.20 ~ 0.35%, Si:0.3 ~ 0.7%, Mn:0.6 ~ 1.0%, Cr:0.7 ~ 1.1%, Ni:0.6 ~ 1.0%, Mo:0.3 ~ 0.7%, all the other are Fe and micro impurity element, ingot casting is carried out forging processing, then-150 DEG C ~ 220 DEG C low-temperaturetempering (soaking time 2 ~ 4 hours) process of 900 DEG C ~ 940 DEG C normalizings (soaking time 1 ~ 3 hour)-880 DEG C ~ 920 DEG C quenchings (soaking time 1 ~ 3 hour) are carried out, it is high that acquisition has high strength, high tenacity, the steel plate of high-wearing feature, weak point is precious alloy Ni, Cr, Mo addition is large, cost of alloy is still higher, thermal treatment process is complicated, process cost and energy consumption are all higher.

China Patent Publication No. is the patent documentation of CN102605234A, disclose a kind of 400HB grade wear-resisting steel plate and manufacture method thereof, its composition by weight percent is: C:0.08 ~ 0.24%, Si:0.1 ~ 0.3%, Mn:0.7 ~ 1.7%, Cr:1.0%, Mo:0.6%, B:0.0005 ~ 0.004%, Ti:0.005 ~ 0.04% all the other be Fe and micro impurity element, casting-controlled rolling-quenching-and-tempering process is adopted to produce, excellent property, be applicable to equipment easy to wear in manufacturing engineering machinery, it is lower relative to continuous casting process efficiency that weak point is to adopt conventional casting techniques, quenching-and-tempering process cost is higher and the production cycle is longer, cost of alloy can reduce further.

Summary of the invention

Pin of the present invention is the deficiency overcoming prior art existence, there is provided a kind of and meeting steel grade intensity and hardness requirement, while having excellent welding property and anti-flame cutting crack-sensitivity performance, cost can be made to reduce by 15%, energy consumption reduces by 25%, the short high-strength abrasion-proof steel plate NM400 of flow process and manufacture method thereof.

Realize the measure of above-mentioned purpose:

A kind of NM400 level cracking resistance line high-strength abrasion-proof steel, its component and weight percent content are: C:0.04 ~ 0.08%, Si:0.20 ~ 0.50%, Mn:1.20 ~ 1.50%, P :≤0.015%, S :≤0.005%, Cr:0.25 ~ 0.60%, Mo:0.20 ~ 0.50%, Ti:0.005 ~ 0.025%, B:0.001 ~ 0.005%, Als:0.015 ~ 0.05%, all the other are Fe and micro impurity element, CEV=C+Mn/6+ (V+Mo+Cr)/5+ (Ni+Cu)/15≤0.57.

Produce a kind of method of HB400 level cracking resistance line high strength martensitic wear resisting steel, its step:

1) smelt also continuous casting and become base;

2) to strand heating, Heating temperature is 1180 DEG C ~ 1240 DEG C;

3) be rolled: control start rolling temperature at 1050 DEG C ~ 1150 DEG C, finishing temperature 950 DEG C ~ 1050 DEG C; Control every time draft 10 ~ 30%;

4) carry out water cooling: control to open cold temperature and be not less than 900 DEG C, under rate of cooling is not less than 20 DEG C/s, controls final cooling temperature and control be no more than 300 DEG C;

5) air cooling is to room temperature;

6) carry out tempering, tempering temperature controls at 200 ~ 400 DEG C; Tempering time is determined according to thickness of slab routine.

When designing the alloying constituent of steel, mainly consider following 2 points: namely to the composition optimization of common alloying elements C, Mn, Cr, Mo and effective utilization of trace additives Ti, B, while meeting steel grade intensity and hardness requirement, production cost is reduced, improves welding property and anti-flame cutting crack-sensitivity performance simultaneously.

Common alloying elements reduces from austenite to ferritic transformation temperature, and the reduction of Ar3 expands austenite non-recrystallization process zone, contributes to more effectively carrying out controlled rolling.Carbon can reduce welding property, therefore will reduce the content of carbon as far as possible, can cause the rising of Ar3 thus, and interpolation Mn, Cr, Mo etc. be relied on to control.Optimal alloy Composition Design should be reduce Ar3 and carbon equivalent as far as possible simultaneously.Mn, Cr, Mo have stronger solution strengthening effect.Mn effectively can reduce critical quenching rate, and Cr, Mo can significantly improve hardening capacity, all helpful to acquisition martensite.But welding property can be caused to worsen for C, Mn, Cr, Mo too high levels and impelling strength significantly reduces, and Cr, Mo content exceedes certain limit easily forms needle type martensite, improves steel belt roof bolt fragility and heat sensitivity.Consider, the composition range devising C, Mn, Cr is: C:0.04 ~ 0.08%, Mn:1.20 ~ 1.50%, Cr:0.25 ~ 0.60%, Mo:0.20 ~ 0.50%.

Trace additives is to following four parameters in controlled rolling, and austenite crystal when namely heating, suppression to recrystallize, transformation behavior and precipitation strength have a great impact.During heating, fine alloy precipitate TiN etc. move and crystal grain thinning by stoping crystal boundary, and micro-TiN precipitate effectively can control the crystal grain-growth after recrystallize.Be solid-solubilized in Ti in austenite when phase transformation or after phase transformation as atomic thin carbide, Carbonitride Precipitation, intensity is raised.So as mentioned above, trace additives is the indispensable composition of controlled rolling.Ti too high levels may cause precipitated phase too to be grown up, and precipitation strength effect will weaken and impelling strength can worsen, and therefore the content of control Ti is 0.005 ~ 0.025%.

In steel, the B element of trace is added in order to improve hardening capacity.The B of solid solution, to the austenite grain boundary place segregation before quenching, by suppressing ferrite transformation, improves hardening capacity.Because in austenite, B can separate out and the effect of impact raising hardening capacity with the form of BN, therefore, also N to be fixed by adding Al or Ti.The especially even solid solution in austenite such as carbonitride generting element of other alloying element, also contributes to improving hardening capacity, and can improve the softening drag in high tempering process.Can hardening capacity be significantly improved when B content reaches 0.0008%, but when B content higher than 0.002% time hardening capacity decline, the toughness deteriorate of steel, and can form low-melting-point eutectic, concentrate on the border of crystal grain, this will cause red brittleness, increase hot worked difficulty.Therefore in the present invention, the content of B is limited to 0.001 ~ 0.005%.

In steel, S, P are detrimental impurity elements, and in steel, P, S content is more low better.When S content is more in steel, during hot rolling, easily produce the problems such as hot-short; And when in steel, P content is more, steel easily occurs cold short, in addition, also easily there is segregation in phosphorus.

Controlled rolling+direct process for cooling is the critical process obtaining martensitic stucture, design key is, control steel high temperature austenite tissue morphology by heating of plate blank, rolling pattern and cooling system, control phase transition process, the organization type of final control steel, form, distribution factor equal to precipitation, meet steel plate design performance requriements.The present invention is by distributing the optimization of rolling pass and draught, and control start rolling temperature and finishing temperature, enter water temp with steel sheet on-line cooling.

The present invention compared with prior art, cost of alloy is low, alloy addition level is less, welding property and anti-flame cutting crack-sensitivity performance excellent, and avoid the energy loss that complicated thermal treatment process brings, significantly shorten the production cycle simultaneously, while there is excellent welding property and anti-flame cutting crack-sensitivity performance, because manufacturing process is simple and flow process is short, cost can be made to reduce by 15%, energy consumption reduces by 25%, process operability improves, therefore there is the very strong market competitiveness and wide application prospect, economic benefit and social benefit obvious.

Accompanying drawing explanation

Accompanying drawing is the metallographic structure of steel of the present invention is the structure iron of tempered martensite.

Embodiment

Below the present invention is described in detail:

Table 1 be various embodiments of the present invention after testing after mechanical property list;

Embodiment 1

A kind of NM400 level cracking resistance line high-strength abrasion-proof steel, its component and weight percent content: C:0.04%, Si:0.37%, Mn:1.40%, Als:0.015%, P:0.01%, S:0.0078%, Cr:0.42%, Mo:0.30%, Ti:0.014%, B:0.0015%, all the other are Fe and micro impurity element, and meet CEV=C+Mn/6+ (V+Mo+Cr)/5+ (Ni+Cu)/15=0.483.

Production stage:

1) smelt also continuous casting and become base;

2) heat strand, heating and temperature control is at 1190 ~ 1200 DEG C;

3) rolling technology: start rolling temperature 1050 ~ 1060 DEG C, finishing temperature 1020 ~ 1030 DEG C, percentage pass reduction: 10%;

4) carry out water-cooled, open cold temperature at 920 DEG C, speed of cooling controls at 23 DEG C/sec, and final cooling temperature is at 295 ~ 299 DEG C;

5) room temperature is naturally cooled to;

6) carry out tempering, tempering temperature controls at 280 ~ 290 DEG C.

Embodiment 2

A kind of NM400 level cracking resistance line high-strength abrasion-proof steel, its component and weight percent content: C:0.062%, Si:0.39%, Mn:1.42%, Als:0.023%, P:0.013%, S:0.0048%, Cr:0.45%, Mo:0.38%, Ti:0.015%, B:0.0013%, all the other are Fe and micro impurity element, and meet CEV=C+Mn/6+ (V+Mo+Cr)/5+ (Ni+Cu)/15=0.512.

Production stage:

1) smelt also continuous casting and become base;

2) heat strand, heating and temperature control is at 1180 ~ 1187 DEG C;

3) rolling technology: start rolling temperature 1090 ~ 1100 DEG C, finishing temperature 1025 ~ 1035 DEG C, percentage pass reduction: 15%;

4) carry out water-cooled, open cold temperature at 930 DEG C, speed of cooling controls at 25 DEG C/sec, and final cooling temperature is at 265 ~ 275 DEG C;

5) room temperature is naturally cooled to;

6) carry out tempering, tempering temperature controls at 270 ~ 290 DEG C.

Embodiment 3

A kind of NM400 level cracking resistance line high-strength abrasion-proof steel, its component and weight percent content: C:0.072%, Si:0.33%, Mn:1.35%, Als:0.022%, P:0.011%, S:0.0022%, Cr:0.26%, Mo:0.47%, Ti:0.021%, B:0.0023%, all the other are Fe and micro impurity element, and meet CEV=C+Mn/6+ (V+Mo+Cr)/5+ (Ni+Cu)/15≤0.57.

Production stage:

1) smelt also continuous casting and become base;

2) heat strand, heating and temperature control is at 1230 ~ 1240 DEG C;

3) rolling technology: start rolling temperature 1120 ~ 1130 DEG C, finishing temperature 1040 ~ 1050 DEG C, percentage pass reduction: 20%;

4) carry out water-cooled, open cold temperature at 940 DEG C, speed of cooling controls at 27 DEG C/sec, and final cooling temperature is at 275 ~ 295 DEG C;

5) room temperature is naturally cooled to;

6) carry out tempering, tempering temperature controls at 310 ~ 320 DEG C.

Embodiment 4

A kind of NM400 level cracking resistance line high-strength abrasion-proof steel, its component and weight percent content: C:0.08%, Si:0.39%, Mn:1.39%, Als:0.027%, P:0.014%, S:0.0029%, Cr:0.43%, Mo:0.42%, Ti:0.019%, B:0.0022%, all the other are Fe and micro impurity element, and meet CEV=C+Mn/6+ (V+Mo+Cr)/5+ (Ni+Cu)/15=0.531.

Production stage:

1) smelt also continuous casting and become base;

2) heat strand, heating and temperature control is at 1203 ~ 1213 DEG C;

3) rolling technology: start rolling temperature 1140 ~ 1150 DEG C, finishing temperature 955 DEG C, percentage pass reduction: 25%;

4) quench online, open cold temperature at 915 DEG C, speed of cooling controls at 22 DEG C/sec, and final cooling temperature is at 245 ~ 265 DEG C;

5) room temperature is naturally cooled to;

6) carry out tempering, tempering temperature controls at 255 ~ 260 DEG C.

Embodiment 5

A kind of NM400 level cracking resistance line high-strength abrasion-proof steel, its component and weight percent content: C:0.052%, Si:0.36%, Mn:1.30%, Als:0.029%, P:0.014%, S:0.0020%, Cr:0.29%, Mo:0.44%, Ti:0.023%, B:0.003%, all the other are Fe and micro impurity element, and meet CEV=C+Mn/6+ (V+Mo+Cr)/5+ (Ni+Cu)/15=0.533.

Production stage:

1) smelt also continuous casting and become base;

2) heat strand, heating and temperature control is at 1210 ~ 1220 DEG C;

3) rolling technology: start rolling temperature 1125 ~ 1135 DEG C, finishing temperature 1030 ~ 1040 DEG C, percentage pass reduction: 30%;

4) carry out water-cooled, open cold temperature at 910 DEG C, speed of cooling controls at 29 DEG C/sec, and final cooling temperature is at 273 ~ 280 DEG C;

5) room temperature is naturally cooled to;

6) carry out tempering, tempering temperature controls at 380 ~ 395 DEG C.

Table 1 be the various embodiments described above after testing after the list of mechanical property situation.

The each embodiment of table 1 is rear mechanical property the results list after testing

Embodiment	Specification/mm	R _eL/MPa	R _m/MPa	A/%	-20 DEG C of ballistic work/J	HBW/10/3000
							1	10	1080	1250	12	55	430
2	20	1070	1230	12.5	65	420
							3	30	1075	1245	12	80	425
4	35	1065	1235	13	70	410
							5	40	1060	1205	14	75	405

As can be seen from Table 1, steel plate thickness specification limit of the present invention is 10 ~ 40mm, yield strength >=1050MPa, Rm >=1200MPa, unit elongation >=12% ,-20 DEG C of Akv >=40J, HBW/10/3000 >=400.As can be seen from example, the plate property adopting thermomechanical processing+tempering process to produce is stablized.

Above-described embodiment is only the best and exemplifies, and is not the restriction to embodiments of the present invention.

Claims

1. produce a kind of method of NM400 level cracking resistance line high-strength abrasion-proof steel, its step:

1) smelt also continuous casting and become base; Its component and weight percent content are: C:0.04 ~ 0.08%, Si:0.20 ~ 0.50%, Mn:1.20 ~ 1.50%, P :≤0.015%, S :≤0.005%, Cr:0.25 ~ 0.60%, Mo:0.20 ~ 0.50%, Ti:0.005 ~ 0.025%, B:0.001 ~ 0.005%, Als:0.015 ~ 0.05%, all the other are Fe and micro impurity element, CEV=C+Mn/6+ (V+Mo+Cr)/5+ (Ni+Cu)/15≤0.57;

2) to strand heating, Heating temperature is 1203 DEG C ~ 1240 DEG C;

3) be rolled: start rolling temperature at 1050 DEG C ~ 1150 DEG C, finishing temperature 955 DEG C ~ 1050 DEG C; Control every time draft 10 ~ 30%;

4) carry out water cooling, control to open cold temperature and be not less than 900 DEG C, under rate of cooling is not less than 20 DEG C/s, controls final cooling temperature and be no more than 300 DEG C;

5) air cooling is to room temperature;

6) carry out tempering, tempering temperature controls at 255 ~ 400 DEG C; Tempering time is determined according to thickness of slab routine.