CN1109919A - Low-alloy wear-resisting steel - Google Patents

Abstract

The low-alloy antiwear steelused as workpieces of dry grinding liner, bulkhead, tooth plate, hammer, protecting plate, etc. for small ball mill, contains C(0.5-0.6), Si(0.9-1.2), Mn (1.4-1.7), Cr (less than 1.35-1.6), Mo (0.3-0.5), V (0.05-0.10), Ti (0.03-0.06), Re (0.02-0.04) and S.P (less than 0.04). The workpiece made of said antiwear steel has service life longer than that of high-Mn steel by more than 1 time.

Description

Low-alloy wear-resisting steel

The present invention relates to a kind of liner plate, bin isolation board, crusher tooth plate, tup, bar that is widely used in the middle-size and small-size ball mill dry grinding of industrial circles such as mine, coal, building materials, the low-alloy wear-resistant steel of workpiece such as backplate.

At present, domestic main employing high mangaenese steel is made these workpiece, high mangaenese steel is a kind of wear-resisting alloy steel of using early, the overwhelming majority is as foundry goods, High Manganese Steel Casting must use after Overheating Treatment-water patent, hardness is HB=179-229 after the water patent, it is organized as single austenite structure, high mangaenese steel is after being subjected to the effect of intense impact power, steel can produce the work hardening phenomenon, sclerosis back HB=450-550, work hardening is to produce in the degree of depth of surperficial 3-6 millimeter, Here it is the wear-resisting reason of high mangaenese steel place.And because high mangaenese steel is single austenite structure, so have excellent impact toughness.

But for middle-size and small-size ball mill, because mill diameter is less, surging force is little, and high mangaenese steel is difficult for forming work hardening layer.

Purpose of the present invention is exactly the working condition requirement little according to mechanical impact force, works out the low-alloy wear-resistant steel that a kind of combination of strength and toughness comparatively is fit to.

The low-alloy wear-resistant steel that the present invention crossed, its Chemical Composition and content are as follows: (weight percent)

C 0.5-0.6

Si 0.9-1.2

Mn 1.4-1.7

S·P ＜0.04

Cr ＜1.35-1.6

Mo 0.3-0.5

V 0.05-0.10

Ti 0.06-0.03

Re 0.02-0.04

All the other are Fe

(1) carbon: content is the key that influences the ferrous materials performance, and the hardness of hardening of the maximum after material is handled depends primarily on carbon content, the too high danger that hardening crack is arranged of carbon containing.So it is 0.5-0.6% that the present invention selects to add the carbon amount according to working condition.

(2) manganese: under given carbon content, increase the most cheap method of hardening capacity and increase manganese content exactly.Manganese reduces the Ar temperature of steel and the decomposition rate of austenite (A) significantly, reduce the critical quenching rate of steel significantly, but manganese can not be too high, and the manganese too high levels will increase the remained austenite content (RA) after quenching.Manganese content of the present invention is controlled at 1.4-1.70%.

(3) silicon: the adding of silicon also can improve hardening capacity and make the first step temper brittleness increase in temperature, silicon has inhibition to austenite (A) grain growth, can offset the side effect that chromatize and manganese bring, but the too high easy generation quenching crack of silicon, so silicone content is chosen in 0.9-1.2%.

(4) chromium: add the hardening capacity that chromium can improve this material, strengthen resistance to corrosion, strengthen resistance to tempering and wear resistance.But excessive chromium is easily separated out needle type martensite, promotes the temper brittleness and the heat sensitivity of steel.For this reason, chromium is limited in 1.35-1.6%.

(5) molybdenum: be a kind of effective fortifier, it can suppress bainite and ferritic transformation significantly, and in quenching and tempered low-alloy wear-resistant steel, molybdenum energy crystal grain thinning, increase hardening capacity and minimizing are to the susceptibility of temper brittleness.Can increase the material resistance to corrosion.Add Cr and the Mo lath martensite that is easy to get simultaneously, can improve the comprehensive mechanical performance of this material.But the molybdenum amount is if too much, easily separate out needle type martensite, and the molybdenum cost is very high.So molybdenum is controlled at 0.3-0.5%.

(6) vanadium: mainly be thinning microstructure, crystal grain thinning, the intensity and the toughness of raising steel form diffusion carbide, improve wear resistance, but the vanadium amount is unsuitable too high, and the too high toughness that then reduces on the contrary is so this programme is controlled at 0.10-0.05%.

(7) rare earth: main effect is cleaning molten steel, good deoxidation, desulfidation are arranged, refined cast structure and improve distribution of carbides, but rare earth can not excessively add, so this programme is controlled at 0.02-0.04%.

(8) phosphorus, sulphur content are low more good more.

(9) titanium: be that extremely strong gentle force element is arranged, but add a little amount of titanium cleaning molten steel, and the crystal grain of thinning microstructure and steel, the add-on that the present invention encourages titanium is controlled at 0.03-0.06%.

φ 1830 * 6120 ball mill bin isolation boards of making of steel grade of the present invention are machine and high mangaenese steel contrast and experiment in fact: former high mangaenese steel bin isolation board work-ing life is 215 days, be 463.5 days bin isolation board work-ing life that steel grade of the present invention is made, and improves more than 1 times work-ing life than high mangaenese steel.

This steel grade mainly is suitable for making the liner plate of middle-size and small-size ball mill dry grinding (φ is below 3.2 meters), and workpiece such as bin isolation board also can be made crusher tooth plate, tup, bar, workpiece such as backplate.

Embodiment 1

Smelting equipment is 1 ton of intermediate frequency furnace,

Going into furnace charge is:

(1) A3 steel scrap, thickness＞5mm does not have serious corrosion,

(2) high carbon ferro-chrome, medium carbon ferrochrome

(3) molybdenum-iron

(4) vanadium-iron

(5) titanium-iron (Ti27-25)

(6) rare earth ferrosilicon (Re30%)

(7) Fe-Si, Fe-Mn, Al bar etc.

Pan feeding Chemical Composition and content are in following ratio proportioning: (weight percent)

C：0.51%;Si：1.0%;Mn：1.6%;Dr：1.42%;Mo：0.35%;V：0.08%;Ti：0.03%;Re：0.025%;S＜0.03;P＜0.024

1480 ℃ of smelting temperature ≈

With steel temperature=1600-1620 ℃

At 1550-1560 ℃ of casting φ 1830 * 6120 ball mill bin isolation boards, be 463.5 work-ing life with this molten steel,

Mechanical property is as follows:

HRC＝52

αk＝28J/cm ²，

6b＝1230MPa

Metallographic structure is: tempered martensite+small portion of residual austenite.

Embodiment 2

With this steel of method smelting of embodiment 1, pan feeding Chemical Composition and content are in following ratio proportioning (weight percent)

C：0.57;Si：0.9;Mn：1.4;Dr：1.35;Mo：0.3;V：0.05;Ti：0.05;Re：0.02;S＜0.02;P＜0.02

Smelting temperature is at 1480 ℃

Tapping temperature is at 1600-1620 ℃

With the liner plate of this molten steel at the 1550-1560 ℃ of middle-size and small-size ball mill (dry grinding) of casting down, 460 days work-ing life.

Mechanical property:

HRC＝50

αk＝3kg5-M/cm ²

Metallographic structure is: M-R

Embodiment 3

Smelt this steel with the method for embodiment 1, pan feeding Chemical Composition and content are pressed routine ratio proportioning (weight percent)

C：0.6;Si：1.2;Mn：1.7;Cr：1.6;Mo：0.5;V：0.1;Ti：0.06;Re：0.04;S＜0.025;P＜0.03

With the molten steel casting crusher tooth plate of this smelting, tup, bar, parts such as backplate, improved 1 times than high mangaenese steel material work-ing life.

Mechanical property:

HRC＝54

αk＝28J/cm ²

Metallographic structure is: M-R

Claims (1)

1, a kind of low-alloy wear-resistant steel is characterized in that: its material Chemical Composition and content are as follows: (weight percent)

C 0.5-0.6

Si 0.9-1.2

Cr ＜1.35-1.6

Ti 0.06-0.03

Mo 0.3-0.5

V 0.05-0.10

Re 0.02-0.04

S ＜0.04

P ＜0.04

All the other are Fe.