CN1067312C

CN1067312C - Cold-welding technique for partially repairing high-carbon alloy steel roller

Info

Publication number: CN1067312C
Application number: CN96115610A
Authority: CN
Inventors: 任登义; 邹增大; 张元彬; 董建
Original assignee: Shandong Polytechnic University
Current assignee: Shandong Polytechnic University
Priority date: 1996-01-10
Filing date: 1996-01-10
Publication date: 2001-06-20
Anticipated expiration: 2016-01-10
Also published as: CN1136985A

Abstract

The present invention relates to a cold welding technology for partially repairing high-carbon alloy steel rollers. The present invention puts forward a theory about liquid deposition toughening of welding seams and strong poor-carbon toughening of a basal body for cold welding with high hardness for the first time, and studies out cold welding technologies of reasonable welding sequence, intermittent welding, hammering of the welding seams, etc. for eliminating welding stress. GTD-30 iron powder welding rods are used for backing welding layers; GT-55 welding rods are used for isolated overlaying welding in divided blocks; GTF-55 welding rods are used for welding surface layers on the periphery; hard metal and soft metal on the welding seams can be combined; large amounts of dispersed globular carbide and cell martensite matrix tissues are formed in deposited metal for welding; the welding state toughness, the abrasion resistance and the fatigue resistance of the welding seams can meet operational requirements.

Description

Cold-welding technique for partially repairing high-carbon alloy steel roller

The invention belongs to steel roll technique for overlaying field, be specially adapted to cold-welding technique for partially repairing high-carbon alloy steel roller.

The high carbon alloy steel roll is the large-scale instrument of rolling stock, because condition of work is abominable, stand strong impact, wearing and tearing, heat fatigue etc., and make the rolling face hardened layer local scaling, be full of cracks occur, cause roll integral body to be scrapped, its improper scrappage accounts for 45%.At present whole preheating surfacing method is mainly adopted in the reparation of high carbon alloy steel roll both at home and abroad, promptly earlier whole roll surface cutting (or grinding) is disappeared to the roll local defect, solid roll is preheated to 400 ℃ then, and keeps this temperature in built-up welding, cooperate alloy welding wire with sintered flux again, along the built-up welding of whole roll surface continuous multilayer multiple tracks,, carry out post weld heat treatment at last until reaching the layer thickness requirement, comprise stress-removal annealing, modified, quench and lonneal, make layer reach the hardness requirement.Not only equipment investment is big for this whole preheating surfacing method, the energy resource consumption height, and repairing efficiency is long, and working condition is abominable, and because of local defect machines away a large amount of intact roll surface hardened layers, causes great waste.

The objective of the invention is to overcome the shortcoming that exists in the prior art, provide the high carbon alloy steel roll that a kind of working condition is good, energy resource consumption is low, quality of welding repair is high, easy to operate local cold-welding technique.

The work top layer of high carbon alloy steel roll is the high rigidity quenching structure, its hardness is generally HRG60-65, the normal temperature impact value is 60-70J, the solderability extreme difference, on the high carbon martensite layer of the former hardened layer of roll, carry out local cold welding reparation, the soldering difficulty is very big, is the long-term unsolved difficult problem of domestic and international welding technology field.The present invention starts with from the Welding Metallurgy theoretical research, the Strengthening and Toughening theory of high rigidity cold welding weld seam liquation malleableize and the poor carbon of matrix is proposed first, and develop the special-purpose surfacing welding of three kinds of cold weldings, utilize rational welding sequence, interrupted soldering, hammering weld seam etc. to eliminate the cold-welding technique of high-carbon alloy steel welding stress.Its key technology is to use the efficient iron powder surfacing welding of the GTD-30 that is developed prime coat, with the upright built-up welding of GT-55 surfacing welding piecemeal arc, with GTF-55 surfacing welding welded perimeter top layer, the periphery fusion area forms in the final stage of soldering, the hard soft combination of weld metal, the dislocatrion martensite matrix of a large amount of disperse globular carbides of formation and high tenacity in the welding deposited metal.High carbon alloy steel roll local defect of the present invention is repaired cold-welding technique, unannealed, the not preheating of breaker roll before the weldering, and postwelding is not done heat treatment, and at room temperature only the full defective of weldering gets final product, and the as-welded toughness of its weld seam, wear-resisting and fatigue resistance can satisfy the instructions for use of roll.

GT-55 of the present invention and GTF-55 surfacing welding, its core wire is H08A, but AC/DC.The coating proportioning of its GT-55 surfacing welding (% by weight) is: marble 30-36, fluorite 18-21, titanium dioxide 3-4.5, manganese metal 4-5.5, high carbon ferro-chrome 4-6, molybdenum-iron 2.5-4, ferrotianium 10-12, solid sodium silicate 4-5.5, composite modifier 19-23.The coating proportioning of GTF-55 surfacing welding (% by weight) is: marble 28-34, fluorite 17-20, titanium dioxide 4-7, manganese metal 1.5-3.5, high carbon ferro-chrome 2.5-4, molybdenum-iron 2-3.5, ferrotianium 9-12, solid sodium silicate 4-6, metallic nickel 4-6, composite modifier 22-26.

In GT-55 and GTF-55 coating composition, marble, fluorite are slag former, ferrotianium is made deoxidier, chromium, ferro-molybdenum are the matrix strengthening element, manganese, nickel increase metallic nickel for control retained austenite element in the GTF-55 components of welding electrode, its effect is suitably to reduce peripheral fusion area to increase dissolving in of carbon because of fusing into of mother metal, and the reduction of chromium, carbon and the increase of nickel help suppressing the formation of high carbon martensite, in case the embrittlement of fusion area.

In GT-55 and GTF-55 surfacing welding, add composite modifier, its role is to significantly improve the toughness of deposited metal, the component of this composite modifier is respectively (% by weight), metal Nb18-32, metal Ti 18-22, metallic Z r13-16, V-F alloy 13-16, rare earth Mg-Si13-16, Si-Ca alloy 9-12, alkali metal compound (Na ₂CO ₃, K ₂CO ₃) 9-12, mud shape graphite 7-9.5.

Adopt this composite modifier, can make surfacing welding have following function: make deposited metal produce a large amount of diffusion carbides, as NbC, TiC, VC impel separating out in early days of carbide, form the liquation carbide, thereby suppressed that secondary is netted separates out, eliminated netted form and produce the effect of liquation malleableize; Utilize Nb, Ti, V strong carbide forming element to capture the carbon in the molten bath, make the poor carbon of weld seam matrix after the crystallization, form the dislocatrion martensite matrix of high tenacity, avoided the generation of high carbon martensite; With element crystal grain thinnings such as Re, Mg, Ca, purify weld seam.When the high-carbon high-hardness roller carries out part reparation cold welding, utilize to add composite modifier, the weld seam comprehensive mechanical performance is significantly improved.

The about GTD-30 surfacing welding of the present invention, core wire is H08A, its coating proportioning (% by weight) is: marble 16-19, fluorite 8-12, rutile 2-4, titanium dioxide 1.5-3, zircon sand 1.5-3, soda ash 1-2, mid-carbon fe-mn 3.5-5, ferrosilicon 3-4.5, ferrotianium 7-9, molybdenum-iron 1.5-3.5, rare earth magnesium 2-4, atomized iron powder 50-55.The GTD-30 welding rod is alkaline high efficiency fe powder covered electrode, deposition efficiency 160-180%, and its as-welded microscopic structure is 100% ferrite, becomes to adhere to separately low-carbon low-alloy steel, HRC20-30.This welding rod is specifically designed to the bottom transition zone built-up welding of roll defect, and its deposited metal plasticity height is extremely low to thermal stress sensitiveness.

For preventing weld crack, the present invention adopts interrupted soldering, hammering weld seam on welding procedure, piecemeal isolates built-up welding, can prevent effectively that the excessive internal stress in soldering district from producing, utilize subregion to isolate soldering simultaneously, each interregional retention gap, deposited metal is expanded with heat and contract with cold the big free degree, to reduce residual stress.In whole welding process, be the basic operation gimmick to disperse the weldering of great-jump-forward point-like, irregular to prevent stress stack and heat energy distribution, the annular fusion area of weld seam and mother metal forms in the final stage of soldering, helps improving the antistripping ability of weld seam.

Three kinds of special-purpose surfacing weldings of the present invention and reparation cold-welding technique, can make the weld zone postwelding be in low-stress state, eliminate sweating heat stress to greatest extent, thereby prevent the fatigue crack in weld crack and the work, solved the local cold welding reparation of high carbon alloy steel roll effectively.GT of the present invention and GTF deposited metal respectively have HRC50 and two series of HRC55, can distinguish the different hardness roll of soldering HRC50-65.(the present invention selects for use weld hardness generally than the low 10-15% of roll surface, and its wearability is suitable).

Embodiment: the high carbon alloy steel roll is local to be repaired, and its surface hardness HRC56 peels off the about 95 * 140mm of area.

After with the angle grinding machine that thin grinding wheel is housed defective being cut earlier, clear up defective and repair the defective groove with flat chisel, hand hammer, again the groove bottom is divided into some soldering district, each is distinguished preset clearance and reaches and the about 8mm in peripheral mother metal gap, with the interrupted jump soldering in each district's scope of GTD-30 surfacing welding, and in good time hammering weld seam, the welding current ground floor is about 230A, each layer is gradually reduced to normal value later on, each district's height of welding bottom is promptly used the GT-50 surfacing welding instead from the about 15mm of roll surface and is carried out soldering, and each distinguishes the soldering height should surpass roll surface 1-2mm.Then, preset clearance is carried out soldering, when filling up the bottom gap, use GT-50 surfacing welding gap, built-up welding top layer again with the GTD-30 surfacing welding.Carry out the soldering of circumferential annular gap at last, with the GTD-30 welding rod along the annular soldering of intermittently jumping, the about 150A of electric current, built-up welding is to the bottom height, with the soldering of intermittently jumping of GTF-55 surfacing welding, last layer height of annular gap should make roll surface and weld seam be rounding off again.The high-carbon alloy steel local defect is behind cold welding, do not come off in the weld seam work, do not chap, its as-welded hardness, wearability, welding crack resistance all can satisfy the requirement of rolling work, prolong the service life of roll effectively, this invention also is applicable to the local defect reparation with the large mold of material, has remarkable economical and social benefit.

Claims

1, a kind ofly utilize rational welding sequence, interrupted soldering, hammering weld seams etc. are eliminated the cold-welding technique of high-carbon alloy steel welding stress, it is characterized in that this technology is with the efficient iron powder surfacing welding of GTD-30 prime coat, with the isolated built-up welding of GT-55 surfacing welding piecemeal, with GTF-55 surfacing welding welded perimeter top layer, the periphery fusion area forms in the final stage of soldering, in GT-55 and GTF-55 surfacing welding, add composite modifier, the hard soft combination of weld metal, form the dislocatrion martensite matrix of a large amount of disperse globular carbides and high tenacity in the welding deposited metal, the coating proportioning of three kinds of surfacing weldings and the component of composite modifier (% by weight) are respectively:

The core wire of a, GT-55 surfacing welding is H08A, and the coating proportioning is: marble 30-33, fluorite 18-21, titanium dioxide 3-4.5, manganese metal 4-5.5, high carbon ferro-chrome 4-6, molybdenum-iron 2.5-4, ferrotianium 10-12, solid sodium silicate 4-5.5, composite modifier 19-23;

The core wire of b, GTF-55 surfacing welding is H08A, and the coating proportioning is: marble 28-34, fluorite 17-20, titanium dioxide 4-7, manganese metal 1.5-3.5, high carbon ferro-chrome 2.5-4, molybdenum-iron 2-3.5, ferrotianium 9-12, solid sodium silicate 4-6, metallic nickel 4-6, composite modifier 22-26;

The core wire of the efficient iron powder surfacing welding of c, GTD-30 is H08A, and the coating proportioning is: marble 16-18, fluorite 8-12, rutile 2-4, titanium dioxide 1.5-3, zircon sand 1.5-3, soda ash 1-2, mid-carbon fe-mn 3.5-5, ferrosilicon 3-4.5, ferrotianium 7-9, molybdenum-iron 1.5-3.5, rare earth magnesium 2-4, atomized iron powder 50-53;

The component of d, composite modifier is respectively: metal Nb18, metal Ti 18, metallic Z r13, V-Fe alloy 13, rare earth Mg-Si13, Si-Ca alloy 9, alkali metal compound (Na ₂CO ₃, K ₂CO ₃) ₉, mud shape graphite 7.