CN1011391B - Serated built-up welding method - Google Patents

Abstract

The present invention relates to a tooth-shaped built-up welding method. Weld is implemented according to the order of 'first-peak and last-valley'. Deposited metal is divided into multiple parts. Welding stress and distortion are reduced in each part, and quality control is implemented in the process of built-up weld. Thus, compared with a conventional cold welding method, the distortion and the stress are reduced by at least 90%.

Description

Serated built-up welding method

The invention belongs to the improvement of overlaying process in the welding field.

Prevent from the welding process to be out of shape and avoid the process of residual stress to be divided into two classes: the one, the hot weld method is carried out weld preheating to the welder of institute part; Postheating can prevent effectively that distortion from eliminating stress, but hot-working causes adverse circumstances to welding, consumes energy, and built-up welding part and built-up welding repair member after being difficult to be adapted to large-scale component or having passed through fine finishining.The 2nd, the cold welding method, it is used for bead-welding technology six kinds of modes: (1) prestrain method; (2) rigid fixation; (3) hammering method; (4) select less welding conditions; (5) open the mitigation channel process; (6) discontinuous welding connection; Above-mentioned six kinds of methods are applicable to various occasion and can reduce distortion and residual stress.Welding stress and welding deformation are very complicated multifactor phenomenons, sum up to get up most important factor and have two: the one, in the Thermal Cycle process, near the plastic strain that produces in the mother metal weld zone, the 2nd, deposited metal is from solidifying cold contraction and the strain of contracting property that is produced during really to room temperature of beginning, generally be caused variations in temperature in welding process, and near the complicated contained STRESS VARIATION that mother metal and deposited metal can not be taken place along with variation of temperature free wxpansion and the contraction welding bead.Eliminate restraining of these complexity so just develop the various welding methods that overcome stress.Usually prevent the method for being out of shape, under situation with spline structure, it is more that what consider is to impose the less heat of mother metal with little weld heat input and short welding bead as far as possible, contained to reduce, and whether the contraction strain of seldom considering welding bead itself (deposited metal) can not impose on mother metal, give mother metal with still less heat and power simultaneously, and can reach resultant effect preferably.Discontinuous welding connection for example, its utilization reduces the length of every welding bead, controlled the heat that imposes mother metal effectively, but also there are two shortcomings in this method in the bead-welding technology process: the one, and no matter every welding bead is divided into several sections, be present on the integral planar but finally still be connected to become a welding bead, though the stress of every section welding bead has reduced, the stress of all each section welding beads still will stack up, all total stress significantly do not reduce, and the 2nd, welding efficiency is lower.

The present invention is in order to overcome the shortcoming of above-mentioned bead-welding technology, to its objective is in order to solve large tracts of land, and is multi-level, than distortion of avoiding in the labyrinth weld deposit process producing and excessive residual stress.

The present invention improves the integral layout of conventional overlaying method, the integral layout of conventional overlaying method is: every welding bead (length no matter, how are width and traffic direction) between all by pressing 1/3rd to arrange mutually, and all be to have arranged ground floor to carry out the second layer again, the 3rd layer afterwards ...Like this, deposited metal finally is an integral body, and its stress also must be the mutual integral body of stack, imposes on mother metal with the stress of integral body, so the welding stress that mother metal bears increases along with the increase of built-up welding deposited metal amount with distortion.Distortion (theoretical calculating) is more than 4 millimeters.And characteristics of the present invention are that (face the harshest to deformation requirements) determined to see Fig. 1 with requiring indeformable parallel welding bead traffic direction on overlaying surface: A is not for allowing deformation plance; B is an overlaying surface; A, b, c, d, e represent the direction of welding bead operation.Definite then vertical with overlaying surface, the position at center is first " peak " position, and " peak " is exactly with deposited metal upwards built-up welding in layer always from the mother metal surface, sees that till the built-up welding height of piling the integral body requirement Fig. 2: H is that integral body requires the built-up welding height; A is a mother metal; Y is first " peak "; 1,2,3,4,5,6,7,8,9,10,11,12 are the built-up welding order.Like this, just formed a dentation that the multilayer welding bead is formed, determined the second, the three according to certain distance with the left and right sides alternating sequence of first " peak " position then in the centre position of overlaying surface ... so that more " peak " position.Just formed a plurality of " peaks " and " paddy " on the surface of built-up welding mother metal, its cross section has just formed zigzag.Then, in " paddy " on both sides, position, first " peak ", choose one wantonly, by alternating sequence " paddy " is filled and led up again as first " paddy " position.Whenever filling out one " paddy " also is from the built-up welding always of " paddy " end to the whole built-up welding that requires highly, and this sees Fig. 3 with regard to the Serated built-up welding method that has formed elder generation " peak " back " paddy ": A is a mother metal; Y is a first peak; Z is first paddy; 1,2,3,4,5,6,7,8,9,10,11,12,13 are the welding order." peak " is as follows with the relation of the physical dimension of " paddy " in the Serated built-up welding method: mother metal thickness: H; Mother metal width: B; " peak " high (deposited metal thickness): F≤1/3H; Weld width (as strong height): H ₁=1/10H; Weld width: B=3H ₁; " peak " bottom width degree: F ₁=(B ₁-1/3B ₁) 3; " paddy " bottom width degree: G=2/3F ₁; " peak " top width degree: F ₂=G; " paddy " top width degree: G ₁=F ₁; " peak " number: F _n=F ₁+ G; Position, first " peak ": Fw ₁=B/2; Welding bead length: L ₁≤ 20B ₁And require the welding rod trend parallel with indeformable.A plurality of " peaks " and " paddy " are divided into numerous part with the integral body of an overlaying surface, and welding stress and distortion have been eliminated in a large number in each part, at last, two last " paddy " are the most concentrated positions of stress at the overlaying surface two ends, and its stress to have reduced to only be this two " paddy " self stress, its welding deformation amount also only is these two variablees that " paddy " can cause, and every layer of welding bead in this two " paddy " all applied hammering, can reduce to minimum to its welding stress generally speaking.The present invention is in order to make distortion and Stress Control in small range (distortion is in 0.04 millimeter) in weld deposit process, dentation built-up welding overall process is implemented monitor closely, at any time the generation of finding micro-deformation and stress just take measures in light of the circumstances (adjusting process parameter) just can make distortion in the weld deposit process and stress can be controlled and counteracting among each local process, become overall error and reach the degree that is difficult to eliminate and be unlikely to superpose.Shown in Figure 4: the fixing framework E that adapts with welded part, while relative fixed welded part B, determine the distortion of mother metal in the welding process with the variable of the relative mother metal A of dial test indicator D fixing on framework surface measuring point, C is a deformation plance, on framework and mother metal correspondence position, determine measurement point, cooperate with the depth chi with dial test indicator, when beginning to weld each time, observe instrumental variable and regulate arcing point, size of current is controlled the variation of welding variable, makes distortion in the dentation weld deposit process and Stress Control in more among a small circle.

Serated built-up welding method of the present invention is divided into one " peak " and " paddy " with deposited metal, except that the ground floor deposited metal was given mother metal more heat and power, the deposited metal that the second layer is above can free shrink be out of shape gradually, the many more heat and the power of mother metal of giving on the contrary of the number of plies are few more, adopt little standard again, hammering, conventional methods such as cooling are handled distortion and the stress that the ground floor welding bead is caused, adopt the present invention just can improve welding efficiency relatively, for example, thickly be=20mm 0.5M at one ²Corrosion resistant plate on, built-up welding rises highly and to be the deposited metal of 10mm, adopt common welding method, discontinuous welding connection and Serated built-up welding method compare, from table-1 superiority of Serated built-up welding method as can be seen, Serated built-up welding method has overcome the shortcoming of interrupted welding aspect the stack of structure binding force, changed the global concept of its welding order, make the stress of built-up welding more than the 3rd layer almost obtain offsetting at deposited metal self, non-conducting imposes on mother metal, drawn simultaneously the advantage of the little heat input of interrupted welding again, prevented to have obtained effect preferably on distortion and the residual stress, given that the cold welding of multiple-bead deposit is indeformable to provide new method.

Embodiment

Continuous polyester 3APA ₁, kettle diameter 1415mm, the long 3841mm of still, still volume are 7.5M ², kettle is a mother metal with Japanese SUS304 stainless steel.The kettle southern side, the stuffing box generation heavy wear of driving shaft needs heap to mend metal and reaches more than 6 kilograms, and stuffing box and kettle are Welding Structure, parts such as stuffing box end face and bearing spider mechanical seal are accurate to be connected, and the reparation welding deformation amount must be controlled at below 0.2 millimeter.Apply 3Kg/cm to the thorough cleaning of welding face and to welding the periphery in the welding process ₂Circulating water.With the handwork tungsten electrode argon arc welding, adopt less heat input, and every welding bead of contact mother metal is imposed 6Kg/cm ₂The air pressure hammering, the Serated built-up welding method that puts in order according to " behind the peak elder generation paddy " welds.After the stuffing box inwall had welded according to per quart girth welding bead, the actual change of amesdial reading was adjusted at any time, determines next welding bead heat input fluctuating range and new arcing point.At any time measure hot conduction scope, interlayer temperature with the welding temperature measurer.Every built-up welding finishes one " peak " or completes one " paddy ", measures stress value, and measures the end face variable with the depth chi.Bead welding 247 roads will be worn and fill and lead up, and stuffing box end face and reset condition differ 0.04 millimeter, are lower than deformation requirements, and stress is within allowable stress range, reduce more than 90% than the theory deformation amount of conventional cold welding method.

Table-1

The common welding method intermittent welding of sequence number project Serated built-up welding method

1 number of weld passes 140 420 280

The wide mm 10 10 6 of 2 welding beads

The long mm 250 85 250 of 3 welding beads

4 every layer of deflection: 1 2.6 0.85 0.09

（mm） 2 2.4 0.73 0.04

3 2.2 0.64 0.015

Horizontal 4 2.0 0.55 0

5 1.8 0.45 0

5 transversely deforming total amounts 11.0 3.22 0.145

6 welding usefulness times (minute) 210 840 500

7 interlayer temperatures ℃ 120 50 50

Claims (2)

1, a kind of welding sequence of utilizing, the method of welding stress and distortion is eliminated in discontinuous welding and hammering etc., it is characterized in that on overlaying surface, the welding bead traffic direction with require indeformable limit of intersecting with overlaying surface parallel, determine vertical then with overlaying surface, the position at center is first " peak " position, " peak " is exactly with deposited metal upwards built-up welding in layer always from the mother metal surface, till the built-up welding height of piling the integral body requirement, like this, just formed a dentation that the multilayer welding bead is formed in the centre position of overlaying surface, determine second according to certain distance with the left and right sides alternating sequence of first " peak " position then, the 3rd, so that more " peak " position, a plurality of " peaks " and " paddy " have just been formed on the surface of built-up welding mother metal, its cross section has just formed zigzag, then, in " paddy " on both sides, position, first " peak ", choose one wantonly as first " paddy " position, by alternating sequence " paddy " is filled and led up again, whenever filling out one " paddy " also is to the whole built-up welding height that requires from the built-up welding always of " paddy " end, at last every layer of welding bead in two last " paddy " of overlaying surface two ends all applied hammering, in the dentation weld deposit process, carry out overall process monitoring and control test surfacing quality.

2,, it is characterized in that " peak " and the relation of " paddy " physical dimension are expressed as follows according to the described Serated built-up welding method of claim 1:

Mother metal thickness is H; The mother metal width is B; Peak height (deposited metal thickness) is F≤1/3H; Bead thickness (strengthening height) is H ₁=1/10H; Weld width is B ₁=3H ₁; Peak base width F=(B ₁-1/3B ₁) 3; The lowest point width G=2/3F ₁; Summit width F ₁=G; Paddy top width degree G ₁=F ₁; Peak number F _n=B/F ₁+ G; The first peak position FW ₁=B/2; The welding bead length L ₁≤ 20B ₁

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