CN1073487C - In-situ welding method for assembling split wheels of large-scale mixed turbine - Google Patents

Abstract

The present invention relates to an on-site assembling welding method for split rotating wheels of large-sized mixed turbines. The present invention is that rotating wheels are manufactured in a split mode according to the number of blades, and the baldes are assembled into a whole through a certain welding process on-site. The present invention can be used for welding a symmetric split rotating wheel or an eccentric split rotating wheel for a large-sized hydraulic turbine, the shrinkage of each weld joint is small in the welding process, and the present invention overcomes the influence on the dimension precision of the rotating wheel, which is caused by the asymmetric assembly stress of an eccentric split rotating wheel with odd numbers of blades and the welding stress; the present invention has high welding quality, short construction period and simple construction equipment; the present invention is an ideal assembling welding method for split rotating wheels.

Description

The method of large-scale mixed turbine split runner building site assembly welding

The invention belongs to the water turbine welding field, be specifically related to the method for a kind of large-scale mixed turbine split runner building site assembly welding.

Francis turbine runner is made up of crown, following ring, blade (general more than 13) and upper and lower seal ring etc.The large-scale water turbine of diameter more than 5.5m be because of the restriction of the restriction that is subjected to condition or casting ability, must the distinguish fabrication and processing, and it is whole that assembled on site becomes, and its assembling mode is divided into following several form:

1) puts the rim of heating at crown and following ring place, rim cooling back is shunk crown and following hoop tight by it, weld blade then, use this kind method construction site that the complicated heating plant of one cover will be arranged, require homogeneous heating, must guarantee the crown flange when being enclosed within crown and down ring being gone up on horizontal plane and can not misplace, the integral forming technique complexity is difficult to guarantee the quality of the whole runner after the welding;

2) crown Bolt Connection, following ring is used the rim hot jacket, welds blade then, and this kind method will have the complicated heating plant of a cover equally, the quality of the whole runner after the same very difficult assurance welding;

3) runner is made loose mail, in building site assembling processing, this kind way requires the building site that complicated job shop is arranged, blade needs blocks of welding, encircles the welding that needs a section down, needs to heat-treat after being assembled into integral body, the equipment volume of heat-treating is big, so the construction period is long, has increased investment, causes waste economically.

The purpose of this invention is to provide that a kind of welding procedure is simple, the building site assembly welding convenient, do not need the method for the large-scale mixed turbine split runner building site assembly welding that special equipment just can weld.

The method of large-scale mixed turbine split runner building site assembly welding is characterized in that this method comprises the following steps:

(1) reaching blade down, the bevel for welding of ring is trimmed to X type and double-U-shaped respectively;

(2) two half runners are placed on the buttress, regulate the wedge shaped plate on the buttress, the respective face of two half runners is on the same horizontal plane, joint face must not collide;

(3) assembling bolt, integrated positioning bolt and pin are packed in the respective aperture of two half runners into pretension assembling bolt and integrated positioning bolt;

(4) integral lifting runner or regulate wedge shaped plate on the buttress, the stress that in two half runner, is produced when discharging pretension bolt;

(5) make the gap of encircling a 5 ± 1mm of formation under the two halves runner with jack, this moment, the following valley of crown flange should be in the scope of 0.2～0.3mm/m;

(6) wedge-shaped blocks is headed into down in the gap of ring, encircling down and place, impeller clearance welding tension plate;

(7) czermak space under the welding forms circumferential weld down;

(8) descend circumferential weld heat treatment, to eliminate welding stress;

(9) the welding impeller clearance forms the blade weld seam.

In the process of czermak space, the following circumferential weld of formation, comprise the steps: under the said welding

(1) will descend czermak space to be divided into plurality of sections;

(2) following czermak space is carried out preheating;

(3) to the back run welding that regresses of following czermak space, welding current is controlled in the scope of 115～135A;

(4) to multilayer room for manoeuvre weldering inside and outside czermak space carries out in order down, welding current is controlled in the scope of 120～150A, and each layer weldering section joint should stagger;

(5) the end layer that following czermak space is carried out from the bottom to top welds, and valley should be in the scope of 0.1～0.2mm/m under the crown flange after following boxing had connect.

Said welding impeller clearance forms in the process of blade weld seam, comprises the steps:

(1) impeller clearance is divided into plurality of sections;

(2) preheating is carried out in the impeller clearance;

(3) to the impeller clearance back run welding that regresses, welding current is controlled in the scope of 110～120A;

(4) impeller clearance is carried out inside and outside multilayer room for manoeuvre weldering in order, welding current is controlled in the scope of 140～170A, and each layer weldering section joint should stagger;

(5) the end layer that the impeller clearance is carried out from the bottom to top welds, and valley should be in the scope of 0～0.07mm/m under the crown flange after blade had welded.

This invention has the following advantages:

1) allows producer because the restriction of railway transport condition divides two lobe manufacturing with rotary wheel of water turbine;

2) can weld the rotary wheel of water turbine of large-scale symmetrical distinguish or eccentric distinguish, weld shrinkage is little during welding, has overcome the asymmetric erection stress of eccentric split runner of odd-numbered blade and the influence to the runner dimensional accuracy that welding stress causes;

3) welding quality height, the requirement of the GB8564-88 that can be up to state standards " hydraulic generator unit mounting technique standard ";

4) construction period weak point, construction equipment is simple, is a kind of comparatively ideal split runner assembly welding method.

Embodiments of the invention are respectively schemed referring to following:

Fig. 1 is the plan view of the eccentric split runner of the present invention, and the blade number is 17;

Fig. 2 is that the A of Fig. 1---A is to view;

Fig. 3 is the plan view of the eccentric split runner of the present invention, and the blade number is 13;

Fig. 4 is that the B of Fig. 3---B is to view;

Fig. 5 is for measuring the measurement view of valley under the eccentric runner crown flange with Straight Steel Ruler;

Fig. 6 is that the C of Fig. 5---C is to view;

Fig. 7 is for ring place arm-tie and top opening are adorned weldering figure down;

Fig. 8 is that the D of Fig. 7---D is to view;

Fig. 9 is for encircling the schematic representation after welding of tension plate and gap head into wedge-shaped blocks down;

Figure 10 is that boxing connects deformation measurement measuring point distribution map down;

Figure 11 is a blade welding deformation measuring point dimensioned drawing;

Figure 12,13 is that boxing connects flow sheet down;

Figure 14 is a double-U groove;

Figure 15 is a double V groove;

Figure 16 is following boxing after-baking curve;

Among the figure:

1---big lobe runner 2---valvula runner 3---integrated positioning bolt

4---assembling bolt 5---positioning dowel 6---crown flanges

7---blade 8---following ring 9---Straight Steel Rulers

10---arm-tie 11---riser 12---gussets

13---jack 14---wedge-shaped blocks

A1, A1 ', A2, A2 ', A3, A3 ' are for encircling measuring point down, and a, b are the measuring point of valley under the crown flange.

Embodiment one:

Single-machine capacity is 30.25 ten thousand kilowatts a hydraulic generator unit, about 59 meters at head, 8 meters of runner nominal diameters, 8.6 meters of maximum diameters, high 5.19 meters, weigh 286 tons, totally 13 blades (as shown in Figure 3), runner adopts eccentric distinguish cast-weld construction, eccentricity value is 160mm, and crown uses the ZG0Cr13Ni5Mo stainless steel material to cast with the casting of ZG20MnSi material, following ring and blade, closing, following ring 8 and divided blade 7 weld the split runner crown on-site with 8 M175mm king-bolts.

1. runner combination

1) at first cleans crown flange 6, integrated positioning bolt 3, assembling bolt 4, positioning dowel 5, bolt hole and the pin hole of runner, remove greasy dirt, burr etc., coat lubricant oil for bolt 3,4 and positioning dowel 5, under encircle 8 and the double-U-shaped groove in blade 7 both sides see metallic lustre with grinder buffing;

2) put 6 buttresses on same horizontal plane, respectively put a pair of wedge-shaped blocks on buttress, require highly unanimity, above big lobe runner 1, valvula runner 2 were placed on reposefully, should notice that runner joint close face must not collide this moment;

3) integrated positioning bolt 3, assembling bolt 4 and positioning dowel 5 are packed into, give bolt pretension stress by the design setting value, make bolt evenly stressed, the pretension stress of each bolt should be consistent;

4) its crown flange 6 joint close gaps, runner combination back can not be passed through with the inspection of 0.05mm clearance gauge; Local gap is not more than 0.1mm, and its clearance gauge degree of depth should be no more than 20% of combinating face girth less than the length between 1/3rd, two measuring points of combinating face respective thickness;

5) but if the on-the-spot integral lifting runner or regulate the wedge-shaped blocks of buttress of having ready conditions, the stress that causes when discharging Bolt Connection, make runner recover reset condition, the combinated seam place grinds one's teeth and is no more than 0.05mm, the circularity of the last oral pore of crown flange 6 should adhere to specification, and radial and axial the grinding one's teeth in weld joint of following ring 8 should be less than 0.5mm.

2. boxing connects under the runner

1) under encircle 8 combinated seam two ends and respectively weld two baffle plates 11 (as Fig. 7), and with gusset 12 supporting baffle 11, with 13 centres of 50～100 tons jack at two baffle plates 11, to descend circumferential weld to back down 5.5mm, it is fixing to weld 3 blocks of tension plates 10 then, a wedge-shaped blocks 14 (as Fig. 9), is respectively squeezed in the upper and lower of weld seam in two in the outside by inboard one; Inside and outsidely in the weld seam both sides respectively stamp symmetrical mark (see figure 10) and will descend ring 8 segmentations, be divided into seven sections, from top to bottom first section 350mm, second section 250mm, the 3rd section 350mm, the 4th section～the 6th section 300mm, the 7th section 250mm;

2) carry out local preheating in the 500mm scope of groove both sides, remove heater when temperature reaches 250 ℃ in the 300mm of groove both sides, welding temperature must not be lower than 150 ℃, and dry good welding rod should be stored in the heat-preservation cylinder more than 70 ℃;

3) the rapid transverse shrinkage of measuring runner behind the dismounting heater, the following valley of crown flanged surface, this moment, valley should be in δ a=δ b=0.4mm/m scope down, at first carry out back run welding, welding rod with the good Austria 237 φ 4mm of drying, welding current is controlled in 115～135A scope, adopt the method for segmentation room for manoeuvre weldering to carry out, weld in following cyclization seam inboard by two welders, a welder regresses from top to bottom and welds preceding four sections, welder is since the 5th section three sections of the postwelding of regressing, two welders carry out simultaneously, after back run welding is finished at outside electricity consumption arc gouge and angle grinding machine back chipping, use dye penetration inspection, then at the welding rod (when instantly ring material for ZG20MnSi adopt T507 φ 4mm welding rod) of each welder of the following interior outside of encircling with LSE one 821 φ 4mm, adopt identical electric current, weldering speed and direction are welded first layer (seeing Figure 12), two welders use the method for the weldering that regresses from following the 6th section of encircling, the 7th section begins weldering, and then be soldered to the 5th section from first section room for manoeuvre simultaneously, for avoiding to arc, behind the starting the arc 10～30mm of one side elder generation, opposite side recurrence arc-welding.Welding current is 120～150A, suitably adjust welding current according to the distortion situation, be the control interpass temperature, requirement is put into several classes and is worked continuously, carry out repeatedly until layer 6 simultaneously in the interior outside, begin to regress from top to bottom from layer 7 and be welded to end layer, capping from the bottom to top at last, layer thickness is 3～5mm, weld width is not more than 15mm, each layer weldering section joint 20～40mm that should stagger, welding bead of every weldering, with pneumatic shovel hammering weld seam, thoroughly cleaning splash, overlap and slag inclusion, use lens examination, weld seam does not allow defectives such as Min crackle, pore, slag inclusion.

Welding contracted quantity mainly is created in preceding 4～6 layers, and therefore, every weldering one deck carries out complete detection one time, and performs record, in time adjusts the inside and outside welding sequence of circumferential weld, layer thickness and welding current down according to the distortion situation simultaneously, with the control welding deformation.

In boxing connects down, should be according to the size of valley under the crown flanged surface, the contraction situation of weld seam different parts, and the factors such as contraction of weld seam judge after the cooling, correctly prescind the tension plate 10 and the wedge-shaped blocks 14 at each position in time, generally begin to cut off successively after welding four, five layers.

Adopt hammering to eliminate stress from the second layer, till face of weld is got even pit.

4) ring heat treatment down

Following boxing is heat-treated after connecing and finishing immediately, burn-on several little hooks or other bump with the colligation heater at down circumferential weld both sides and end face according to the heating tape size, the size of heating tape generally is 4～7 times of following ring thickness, according to heater size, power is divided into some groups, thermocouple is installed in both sides inside and outside following circumferential weld, to detect heating-up temperature, thermocouple, heater is incubated after arranging, heat (seeing Figure 16) according to heating curve then, the longitudinal axis is the temperature coordinate, transverse axis is a time coordinate, and the temperature during heat treatment around the runner is not less than 20 degree.

3. the welding of blade

1) the blade weld seam is divided into the A side, the B side, every side weld is divided into five sections from top to bottom, stamp corresponding measuring point, distance between first pair of measuring point of A side and the blade tip is the 800mm radian, distance between the second pair of measuring point and the first pair of measuring point is the 750mm radian, distance between the 3rd pair of measuring point and the second pair of measuring point is the 900mm radian, distance between the 4th pair of measuring point and the 3rd pair of measuring point is the 1000mm radian, distance between the blade bottom and the 4th pair of measuring point is the 1000mm radian, before the welding blade being preheating to 80～100 spends, the blade mismatch is not more than 3mm, pass through template, jack is adjusted, and at 3～4 arm-ties of face bonding, uses 237 φ 4mm welding rods difficult to understand then, every 500mm joint welding one segment length 30～50mm, thickness 6～8mm;

2) carry out back run welding, with 237 φ 4mm welding rods difficult to understand, segmentation from top to bottom regresses and welds, every section 300～400mm, and welding current 110～120A uses air-arc cutting and angle grinding machine back chipping overleaf, carries out dye penetrant inspection;

3) behind the back chipping with the welding of LSE-821 φ 4mm welding rod, each blade by two welders from top to bottom symmetry weld, four welders weld the intact hammering of two every welderings of blade once simultaneously, welding current 140～170A welds thick 3～4mm;

4) welding deformation is controlled, is monitored with ring is the same down, need control the following valley of crown flanged surface equally, and the following valley of crown flanged surface was controlled at 0～0.07mm/m after the blade welding was finished.

Embodiment two:

Single-machine capacity is 320,000 kilowatts a hydraulic generator unit, about 120 meters at head, 6 meters of nominal diameters, 6.6 meters of maximum diameters, high 3.06 meters, weigh 145 tons, totally 17 blades (as shown in Figure 1), runner adopts eccentric distinguish cast-weld construction, eccentricity value 250mm, and crown is cast with the ZG20MnSi material, following ring is the casting of 20MnSi material, closing, following ring and divided blade weld blade on-site with 8 M175mm king-bolts with ZG0Cr13Ni5Mo stainless steel material casting, split runner.Following boxing connects technology referring to Figure 15, to descend ring to be divided into five sections, at first carry out back run welding, welding rod with the good Austria 237 φ 4mm of drying, welding current is controlled in 115～135A scope, adopt the method for segmentation room for manoeuvre weldering to carry out, carry out back cover by the welder weldering that regresses from top to bottom in following cyclization seam inboard, after back run welding is finished at outside electricity consumption arc gouge and angle grinding machine back chipping, use dye penetration inspection, each welder adopts identical electric current with the welding rod of T507 φ 4mm in the interior outside of encircling down then, weldering speed and direction are welded first layer, and two welders begin to weld from the 5th section of encircling down with the method for the weldering that regresses, and then be soldered to the 4th section from first section room for manoeuvre simultaneously, for avoiding to arc, behind the starting the arc 10～30mm of side elder generation, opposite side recurrence arc-welding.Welding current is 120～150A, suitably adjust welding current according to the distortion situation, be the control interpass temperature, requirement is put into several classes and is worked continuously, carry out repeatedly until the 15 layer simultaneously in the interior outside, since the 15 layer since down the uneven gauge of ring weldering section reduce gradually until the end layer, capping from the bottom to top at last, other monitoring method is with embodiment one.

Claims (3)

1. the method for large-scale mixed turbine split runner building site assembly welding is characterized in that this method comprises the following steps:

(1) reaching blade down, the bevel for welding of ring is trimmed to X type and double-U-shaped respectively;

(2) two half runners are placed on the buttress, regulate the wedge shaped plate on the buttress, the respective face of two half runners is on the same horizontal plane, joint face must not collide;

(3) assembling bolt, integrated positioning bolt and pin are packed in the respective aperture of two half runners, squeeze into positioning dowel fixing after, pretension assembling bolt and integrated positioning bolt;

(4) integral lifting runner or regulate wedge shaped plate on the buttress, the stress that in two half runner, is produced when discharging pretension bolt;

(5) make the gap of encircling a 5 ± 1mm of formation under the two halves runner with jack, this moment, the following valley of crown flange should be in the scope of 0.2～0.3mm/m;

(6) wedge-shaped blocks is headed into down in the gap of ring, encircling down and place, impeller clearance welding tension plate;

(7) czermak space under the welding forms circumferential weld down;

(8) descend circumferential weld heat treatment, to eliminate welding stress;

(9) the welding impeller clearance forms the blade weld seam.

2. welding method according to claim 1 is characterized in that comprising the steps: in the process of circumferential weld under czermak space under the said welding, the formation

(1) will descend czermak space to be divided into plurality of sections;

(2) following czermak space is carried out preheating;

(3) to the back run welding that regresses of following czermak space, welding current is controlled in the scope of 115～135A;

(4) to multilayer room for manoeuvre weldering inside and outside czermak space carries out in order down, welding current is controlled in the scope of 120～150A, and each layer weldering section joint should stagger;

(5) the end layer that following czermak space is carried out from the bottom to top welds, and valley should be in the scope of 0.1～0.2mm/m under the crown flange after following boxing had connect.

3. assembly welding method according to claim 1 is characterized in that said welding impeller clearance, forms in the process of blade weld seam, comprises the steps:

(1) impeller clearance is divided into plurality of sections;

(2) preheating is carried out in the impeller clearance;

(3) to the impeller clearance back run welding that regresses, welding current is controlled in the scope of 110～120A;

(4) impeller clearance is carried out inside and outside multilayer room for manoeuvre weldering in order, welding current is controlled in the scope of 140～170A, and each layer weldering section joint should stagger;

(5) the end layer that the impeller clearance is carried out from the bottom to top welds, and valley should be in the scope of 0～0.07mm/m under the crown flange after blade had welded.

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