CN1132264A - Low alloy wear-resisting steel - Google Patents

Abstract

A low-alloy high-strength antiwear martensite steel used to manufacture easily abrasive workpieces such as liner of cylindrical body, end liner and isolating plate contains the components such as C (0.25-0.50), Si (1.0-1.5), Mn (1.5-1.9), Cr (1.0-1.40), Mo (0.2-0.4), V (0.05-0.10), B (0.001-0.003), Re (0.02-0.05), P (less than 0.04) and S (less than 0.04). The workpieces made of such steel have high impact toughness, breaking toughness and abrasion and corrosion resistances.

Description

A kind of low-alloy wear-resistant steel

The present invention relates to a kind of shell liner, aside-liner that is widely used in industrial circles such as mine, coal, building materials reaches every the High-Strength Low-Alloy Ma Shi of wear-resisting consumable accessorys such as daughter board wear resisting steel.

At present industrial sector ball grinding machine lining boards such as metallurgical mine and coal are domestic generally all gets used to adopting ZGMn13, hard (Ni-HaRd) cast iron of domestic employing nickel or general low-alloy wear-resistant steel.Differ greatly work-ing life, is generally half a year or more more time.State 0.25 kilogram of/ton mine of interior lining panel abrasion average out to.Make ball grinding machine lining board with ZGMn13 and be difficult for forming the shock peening layer for middle-size and small-size grinding machine; To wet mill, because the viscosity of ore pulp and the shock absorption of ball layer, more can not make high mangaenese steel produce good work hardening, the wear-resisting potentiality of ZGMn13 are not in full use, and that ni-hard cast iron belongs to the hard brittle material impact value is too low, application is restricted, and the ball grinding machine lining board design aspect is not done before the corresponding change at home, the employing of can not gently anticipating.Moreover nickel is rare noble element, according to the china natural resources situation, does not also allow to use.

And general low-alloy wear-resistant steel, owing to can not guarantee liner plate hardness and impelling strength good combination on material Chemical Composition and the production technique, cause general low-alloy steel liner in use to be prone to two kinds of situations: liner plate hardness is had a surplus, but toughness deficiency, cause the product cracking: toughness is had a surplus, but the hardness deficiency causes descend work-ing life.Most cases is, low-alloy wear-resistant steel hardness height, and major defect is the toughness under-reserve, application is restricted.

Purpose of the present invention is exactly on conventional low-alloy wear-resistant steel basis, according to the requirement of working condition, works out a kind of enough hardness that both guaranteed from the material Chemical Composition to production technique, and the High-Strength Low-Alloy martensite wear-resistant steel of proper toughness is arranged again.

This low-alloy wear-resistant steel of the present invention, its Chemical Composition and content following (weight %)

C 0.25-0.50

Si 1.0-1.5

Mn 1.5-1.9

P ≤0.04

S ≤0.04

Cr 1.0-1.40

Mo 0.2-0.4

V 0.05-0.10

B 0.001-0.003

Re 0.02-0.05

All the other are Fe

(1) carbon: content is to influence one of ferrous materials performance most critical, topmost element.No exception for High-Strength Low-Alloy martensite wear-resistant steel of the present invention.Maximum after material the is handled hardness of hardening depends primarily on carbon content.Alloying element is little to the influence of the highest hardness of material, but alloying element has influence on the degree of depth that specific dimensions and section highest hardness can reach dearly.Therefore, the present invention emphasizes that the hardness (hardness of hardening) of product needed determines the carbon content of material.The too high danger that hardening crack is arranged of carbon containing.So the present invention determines carbon content a wider range of material: 0.25-0.50%.Can select lower limit, middle limit and higher limit for use 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, and manganese also can reduce to the person of showing the critical quenching rate of steel, but manganese can not be too high, and too high manganese content will increase the remained austenite content (RA) after quenching.Manganese content of the present invention is controlled at 1.5-1.9 (%).

(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 being chosen in 1.0-1.5%, silicone content is advisable.

(4) chromium: this material adds a certain amount of chromium, concludes and gets up to have three effects:

(i) improve the hardening capacity of this material;

(ii) strengthen resistance to corrosion;

(iii) 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 1.0-1.4 (%).

(5) molybdenum: molybdenum is a kind of effective fortifier, and 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.Molybdenum is similar to chromium, can increase the material resistance to corrosion.Add Cr, 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 order molybdenum cost is very high.So molybdenum is controlled at 0.2-0.4% is advisable.

(6) vanadium: the principle that can improve hardening capacity according to several alloying elements of a small amount of adding than a large amount of one or both alloying elements of adding effectively.Vanadium of the present invention adds as the microalloying element.V-arrangement becomes VC or V4V3 and VN, and hardness is very high; V energy crystal grain thinning improves wear resistance, adds certain vanadium and helps martensitic transformation.But vanadium is a noble element, and vanadium amount of the present invention is controlled at the micro-scope of 0.05-0.10%.

(7) rare earth-boron compound modifier: China's rare earth and boron aboundresources.Price is also cheap.The mechanism of rare earth in steel is not understood at present yet fully.But main effect that it is generally acknowledged rare earth is a cleaning molten steel, can reduce " O ", " H ", " S " content, improves nonmetal inclusion shape, size and distribution, and column crystal can be eliminated or alleviate to crystal grain thinning.Boron has the strong hardening capacity ability of improving steel, and this is the main effect of boron in this material.

The present invention adopts the Re-B composite inoculating to handle to wear-resisting molten steel.Its objective is the toughness α that improves the martensite wear-resistant steel _k(J/cm ²) empirical evidence: whether molten steel goes bad, and material toughness truly has than big-difference, evidence: with rare earth or the rotten separately processing of boron, the material flexible is improved not as good as handling with rare earth-boron composite inoculating.

But excessive rare earth and boron amount are unallowed.The boron amount is too much, and the fragility that the boride that brilliant Jie goes up boron can be directed at steel increases; Rare earth content is too much, also will have the opposite effect.So regulation B=0.001-0.003% Re 0.02-0.04%.

(8) phosphorus, sulphur content: phosphorus, sulphur content are low more good more.Material regulation P of the present invention, S content≤0.04%.

Low-alloy wear-resistant steel of the present invention is given full play to the china natural resources advantage, utilizes boron (B), the effect of rare earth (Re) compound modifier, improves impelling strength (α _k) and fracture toughness property (Kic) value.Occur in martensite for guaranteeing to lure in the larger cross-section liner plate, add the alloying element that guarantees hardening capacity in the steel: Si, Mn, Cr, Mo.And the Mn, the Si element that make full use of cheapness consciously carry out alloying.Add a spot of vanadium (V), as micro alloying element.Add Cr and Mo, except that improving wear resistance, certain erosion resistance is also arranged.

Embodiment 1

Smelt this low-alloy wear-resistant steel with basic electric arc furnace, Chemical Composition adds in the molten steel in following ratio proportioning (weight percent),

C 0.4

Si 1.0

Mn 1.6

Cr 1.2

Mo 0.25

V 0.08

B 0.0017

Re 0.03

P ＜0.03

S ＜0.02

Smelt:

At first electric-arc furnace steelmaking, oxidation period decarburized amount 〉=0.35%C, the white slag reduction,

Add Re-B then, to the molten steel processing of going bad,

Can be in steel teeming ladle after the tapping Argon (Ar).Pressure ≈ 0.03MPa, the time is 2-3 minute.

Smelt good molten steel casting φ 1.5 * 1.5m ball grinding machine lining board with this, work-ing life, mechanical property was as follows than having improved about 1.5 times the work-ing life of high mangaenese steel:

HRc=50.5, impelling strength α k58J/cm ², fracture toughness property Kic=117MPa/M, breakdown point=1680MPa, yield strength δ 0.2=1274MPa,

The gained metallographic structure is after Overheating Treatment:

Tempered martensite+a small amount of lower bainite+small portion of residual austenite

Embodiment 2

Smelt this low-alloy wear-resistant steel Chemical Composition with embodiment 1 described method and add in the molten steel in following ratio proportioning (weight percent),

C 0.5

Si 1.5

Mn 1.9

Cr 1.40

Mo 0.4

V 0.10

B 0.003

Re 0.05

P 0.04

S 0.04

Smelt good molten steel with this and cast medium and small wet-type ball mill liner plate, though the too late high violent steel of its shock resistance, the impelling strength that it possessed is higher than high steel suddenly comprehensive friction durability fully applicable to this class working condition.Cost is lower than high violent steel.

Mechanical property is as follows:

Breakdown point δ _b=1670MPa

Yield strength δ=1270MPa

Impelling strength α _kJ/cm ²

HRC＝50

Fracture toughness property Kic=117MPa/M

The gained metallographic structure is after Overheating Treatment:

M returns+B (on a small quantity)+RA (on a small quantity)

Embodiment 3

Smelt this low-alloy wear-resistant steel with embodiment 1,2 described methods, Chemical Composition adds in the molten steel in following ratio proportioning (weight percent).

C 0.25

Si 1.0

Mn 1.5

Cr 1.0

Mo 0.2

V 0.05

B 0.001

Re 0.02

P 0.02

S 0.01

Smelt good molten steel with this and cast broken tooth plate, tup, workpiece such as bar, backplate, pair roller are much higher than high violent steel work-ing life, and cost is lower than high violent steel.

Mechanical property is as follows:

HRC＝50.5

Impelling strength α _k58J/cm ²

Breakdown point σ _b=1765MPa

Yield strength σ _s=1430MPa

Fracture toughness property Kic=117MPa/M

Metallographic structure after the tempering:

M returns+B (on a small quantity)+RA (on a small quantity)

Claims (2)

1. a low-alloy wear-resistant steel is characterized in that: its material Chemical Composition and content following (weight percent)

C 0.25-0.50

Si 1.0-1.5

Mn 1.5-1.9

Cr 1.0-1.40

Mo 0.2-0.4

V 0.05-0.10

B 0.001-0.003

Re 0.02-0.05

P ≤0.04

S ≤0.04

All the other are Fe

2. the preparation method of a low-alloy wear-resistant steel is characterized in that:

(1) electric arc furnace smelting, oxidation period decarburized amount 〉=0.35%C, white slag reduction,

(2) make recombiner to the molten steel processing of going bad with Re-B,

(3) molten steel is made Argon and handle, pressure ≈ 0.03MPa, the time is 2-3 minute.