CHINA MINI BIKE

This procedure provides the basic requirements for copper and copper alloy welding, GTAW for copper and copper alloy, welding, melting inert gas welding and automatic submerged arc welding of copper and copper alloy single container lined copper container, copper welding process.
Welding materials:

Welding argon purity ≥ 99.99%, dew point ≤ -50 ° C, and shall conform to the provisions of GB/T4842 or GB10624. When the bottled argon pressure ≤ 0.5Mpa unfit for use. When preheat inconvenient or require penetration when available 70% Ar +30% N2 gas mixture. Nitrogen and helium as shielding gas is argon penetration of 2 to 3 times, but nitrogen gas pores increased tendency.
Two.
GTAW electrodes with cerium tungsten electrodes. The electrode diameter should be selected according to the welding current size (using the general requirements than the welding current specifications One tungsten),
3.
The main role of the flux is to remove the oxide film, and other impurities, to prevent the molten pool of metal oxide and other gas into the bath, and improve the flow of liquid metal. Available when using absolute alcohol into a paste or flux powder on the groove and on both sides and then welded or wire ritual flux. You can also use gas shielded arc welding flux to enhance the protective effect of the weld pool.
4.
The more important structures in order to eliminate the adverse effects of oxygen, must be selected with strong deoxidizer such as aluminum, titanium wire; can be used in order to prevent the alloying elements in the oxidation and evaporation during the welding process: welding brass (to prevent the zinc oxide and evaporation) silicone wire and rapid welding to reduce the high temperature residence time when the solder bronze (tin to prevent oxidation and evaporation) can be silicon, phosphorus and other deoxidizer wire with borax and boric acid flux, welding aluminum bronze (to prevent aluminum oxidation and evaporation ) can be used chloride salt and fluoride salt flux.
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Second, welding welder:
A.
Should GB50236 the provisions site equipment, industrial pipe welding in the construction and acceptance of "passing the examination.
Third, before welding to prepare:
A.
Flame ionization method for processing from the color part of the machining to remove copper groove processing should be used by mechanical means (including shear), such as the use of not less than 3mm, the groove processed surface should be flat, smooth, without cracks, delamination , inclusions, burrs, flash and oxidation color. Groove surface was metallic luster; the groove and on both sides when necessary, should normally be not less than 30 mm within 100% PT. . D3, X-: ~ 4 Z% K! E3 @ /]
Two.
Wire, not less than 30 mm range must be the surface of the water surface and sides of the groove, the oil spill to clean up (including to the surface of the oxide film, scales, pollution and the failure of oxidation color). Available φ0.15 ~ 0.2 stainless steel wire tray polished brush metal grinding head, and acetone (acetone-moistened cloth should be clean, do not use cotton or cotton, in order to avoid a wipe with a plush), it should be noted that these tools prior to use clean up; try not to use the grinding wheel.
3.
Assigned parts of the thermal processing, such as closing the first class, in principle, into the plant response to the copper surface of 100% of the PT, when necessary, parts can not be determined by RT. 8 H [/ V0 P8 {1 P-P
4.
Wire surface can be used stainless steel wire brush or a clean oil sandpaper to scrub; also need chemical cleaning surface oxide thick wire polished before welding. Chemical cleaning: HNO375cm3 / L + H2SO4100cm3 / L + HCl75cm3 / L mixture of cleaning, and then the alkaline wash, and finally drying with a clean rinse hot air. Copper also can refer to this method. ; O5 Z7 ^ 3 u% m; Z-
5
Clean welding wire and welding should be kept clean and dry by hand may not touch the welding position, welding is prohibited pollution, or should be re-clean up local pollution can be partially re-clean-up; best with a white cover on both sides in the groove . Not welding, such as clean up after 8h ago should be re-weld clean up. Y A4 O $ 4 r4 d, D (w ]! W
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Weldment assembly should be accurate, should be considered if the assembly of non replacement parts, and not to force the group to avoid causing too much stress. In deal with groove dimensions to be checked before the formal welding, and after passing the welding.
7.
The selection of tack welding wire and take process measures and welding.
8.
Weldment group in the stress concentration (such as the weld at the intersection and the workpiece on the corner, etc.) to avoid tack welding, positioning the weld without cracks, porosity, slag and other defects, otherwise it must be removed to re-welding. Heavy welding should be carried out in the nearby area, rather than in the original spot.
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Arc panels and back arc plate welded longitudinal seam must be placed at both ends of the weldment, arc boards and back-arc plate and welded the same grade and thickness of copper. Welding girth try to avoid the crater. # N6, B, l7 W * c
10.
Positioning solder joint cracking during the welding process, resulting in the board edge dislocation or gap change, you should immediately stop welding, in order to continue after repair welding. 3 `1 K, the" w v $ the A6 [
11.
The plate material is generally produced graphite plate, because the graphite thermal conductivity and slow, good insulation. When the copper thick plate assembly gap can be used clay mud to seal the gap, can be removed after welding. Flux (in this case the submerged arc welding such as HJ431) can also be used if the current large should also consider the flux layer should have a certain thickness. Plate size in the figure: | 0: n% Y8 V5 _ * f Z6 T4 in a
Welding requirements: 1 i Q, X9 @ ( $ I, E, & e
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Qualified welders shall be welded to the welding process files and other documents. ; D-L m1 is [r
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In the welding environment is one of the following conditions, should take effective protective measures will not be permitted welding: v + s # o5 r (? E; the F
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Welding environment dirty, dust, smoke;
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Welding environment wind speed is greater than or equal to 1.5m / s; 5] 2 o3 U! D, o2 U / Q
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Welding environment relative humidity greater than 80%;
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Rain, snow outdoor operations;
5)
Soldering temperature is below 5 ° C;
3.
Copper welding located in a dedicated venue, the venue shall be paved with rubber or flannel; welding should be away from the vents and doors and windows to avoid the effect of gas protection.
4.
Manual tungsten inert gas welding welding pure copper, brass (Cu-Zn), tin bronze (Cu-Sn) and copper-nickel alloy (Cu-Ni) with the DCSP; aluminum bronze (Cu-Al) and silicon bronze (Cu -Si) AC to remove the surface oxide film. Melt TIG welding and automatic submerged arc welding using DCRP. 8 a3, I4 M7, S & the F4 o # w # N; v * n
5
Should preheat before welding preheating: strong copper thermal conductivity, therefore general GTAW welding is greater than the thickness of 4mm pure copper 4 ~ 12mm preheat 200 ~ 450 ℃; bronze and copper-nickel alloy Pre-150 ~ 200 ℃; silicon bronze and phosphor bronze may from time to preheat and control interpass temperature does not exceed 100 ℃. Depending on the particular circumstances flame or far infrared panels for heating. # ~! Y / O $ h4 the T9 U the A9 @ I
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Welding copper and bronze are generally neutral flame, oxidizing flame could easily lead to element burning, reducing flame containing H and prone to porosity. Brass with a weak oxidizing flame, in order to generate zinc oxide and off the H reduce pores. Gas welding groove is generally not the only single-sided single-layer welding, to avoid multiple multi-pass welding deformation. To grain refinement after welding, hammering, such as the plate thickness does not exceed 5mm along the weld on both sides of 100mm at the hammer, when the thickness is greater than 5mm can be first heated to 500-600 degrees hammering, and then heated to 500 to 600 degrees water is chilling.
7.
A weld should first welding finished, forced to a stop after welding, welding, overlap 10 to 20 mm. Thoroughly to remove surface contamination, slag and other defects. Crater should be filled, then the arc at the fusion penetration. General extinction heap high extinction law: Crater uniform elevation arc, while accelerating the filler wire, until the arc goes out, the extinction at the weld local bulge, if necessary, polished excessive I. Attenuation device on welding machine, arc this off better. F-W% r @ d (f "_ / K) U
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C and Class D connector weld and parent material was a smooth transition. ; The V8 f + Z # F & [0 {8 N $ J
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The surface of the weld and heat affected zone should be carried out 100% inspection, no cracks, incomplete fusion, porosity, craters, slag and spatter defects in the weld outside should not fight the arc spot.
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Copper pressure vessel weld surface should not be undercut. Undercut depth of the weld surface of the pressure vessel should not exceed 0.5mm, undercut continuous length should not exceed 100mm, total length of the undercut of the weld on both sides of the weld length should not exceed 10%.
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Should be noted that copper welding of overhead position welding is not easy to achieve, generally do not arrange such a position. 9 Z6 0? 0 of P (E1}; c & u! Y3 M; p
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Heat exchanger heat transfer tube welding sequence: the tube plate assembly (heat transfer tube set aside shall be not less than 4mm in length, so that the back of the machine processing); tube-side and tube sheet cleaning; one end of the expander; welded side tube plate; machining is not welding The heat exchange tubes tube end; expander; tube-side and tube sheet clean-up; welding heat transfer tube is not welded side. Welding the first layer is generally not the Lifting welding (the first layer of whether PT or air tightness testing required), but other layers should Holes welding.
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, Weld repair: d # y & e # D * T7 in K1, X-
A.
Should analyze the need to repair the defect causes, suggest improvements, and the preparation of welding repair process (consider machining installed anti-welding deformation) to rework (table weld defects under normal circumstances and the reasons for analysis);
Two.
The same parts of the weld repair number of not more than two times. -] N6, m,! K + j% ~ & L6 U $ M5, p
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General metal grinding head clear of defects and groove. Defects deeper, you can use the prescribed manual milling grinding, and then the metal grinding head polishing the surface of the groove. Groove width of the uniform, smooth surface and ease of welding groove, the groove at both ends of a certain slope (generally not more than 1:3). , P. `[9 the M8 the J-O0 Q-
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Rework before defects need to be cleaned, should generally be 100% PT to confirm (if the defect is a crack, it must be 100% PT). Welding when defects divisible can not dig deep, when necessary, RT confirm the defect has been completely removed. First, not when welding with filler wire, metal melting arc welding District; filler wire arc should be a little biased wire, anti-welding metal overheating in arc welding length direction modest move back and forth to extend the bath exist time, in order to facilitate the hydrogen bubbles escaping from the molten bath.
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Repair weld performance and quality requirements should be the same as the original weld;% h z4 f w) `9 z-
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Copper welding weld defect pores and cracks:
6.1 stomatal causes: Copper Weld porosity is mainly hydrogen into the weld pool formed. Sources of hydrogen are: material, welding wire, shielding gas, wire feeder, welder s gloves and environmental humidity is too high, such as wire contaminated material and wire the oxide film, wire feeder, oil or condensate perspiration. Preventive measures:
6.1.1 Materials and hydrogen content in the wire ≤ 0.4mL / 100g; & the z9 h8 h1 @ $ J6, E4, "~: u
6.1.2 was the weldment surface should remove the oil and oxide film, the storage time of not more than 4h. Surface cleaning dry clean, lint objects cover the groove and on both sides; 2 w (w8 B H2, l4 b0 q @
6.1.3 wire to make use of polished wire, or processing as above; 0 S (v1 Y8 B + `/ w" O: F
6.1.4 shielding gas impurities: H2, ≤ 0.001%; ??of O2 ≤ 0.02%; N2, ≤ 0.1%; H2O, ≤ 0.02%; + t: X: V0 p1 is i $ i $ R9, a, E-]
6.1.5 protect the gas pipeline: the general use of stainless steel pipe or copper tube, hoses plastic tube without the use of rubber and other easy to absorb water hose; should check the cooling water pipes before welding to ensure no leakage; When the environment is very humid deal with the protective gas is heated to purge piping; [5 L + qm * `6 t4 _
6.1.6 to send the wire agencies: Do not oil, wire with Teflon tubing before welding and clean up pollution and condensation of water in the tube;
6.1.7 The environment of the scene: the temperature should not exceed 25 ℃, relative humidity of not more than 50%, keeping the environment clean; the F-U) A!] +
6.1.8 Welder: Work clothing as much as possible is white, in order to timely detect and clean up pollution. When welding sweat and grease do not re-contaminated weldments; x * N! W $ m1 is Y8 ^ 1 h0 the R
6.1.9 should be in the test panel before welding test welding, in order to check whether the protection of gas and pipeline qualified.
6.1.10 The welding process on preventive measures instead of single-sided welding: welding with double-sided; each weld thin than thick, the pores escape; large diameter wire to reduce the pores; preheat and slow cooling after welding ; lower arc voltage, increasing the current, lower welding speed, and helps to reduce the pores. % O) L + t p9 f I7, K & the Z8 O $ n, {the G8 u
6.2 crack causes: material weldability is poor; select the wire did not consider the crack resistance; structure binding spent. Preventive measures: & o1 G $ A {0 Q8 M B # [4 @ W
6.2.1 poor weldability of copper before soldering should consider the crack can not only consider the strength; necessary, consider the weldments were annealed after welding, welding and then quench aging. V * A; P #] 2 [+ Z # G. The W j
6.2.2 Select the anti-crack and good wire, such as those containing Si in low-melting-point element of the wire.
6.2.3 minimize the degree of binding of the welded joints, and reasonable arrangements for the welding sequence to weld horizontal shrinkage margin, to reduce welding stress. There is no need to tack welding, do not weld tack welding, double-sided, do not tack welding sided tack welding.
6.2.4 as far as possible to change the one-side welding for double-sided welding. E) I-s (b
VI testing requirements:
A.
Patchwork welding of the head should be 100% RT, forming before the provisions of 100% RT or 100% PT.
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A and Class B welds are generally 100% by RT.
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Class C, D, welded joints in the container 100% PT.
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Copper surface welding weld 100% PT.
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After the removal of copper fixtures and reinforcement of temporary fixed connection weld welding marks 100% PT.
6.
Other design requirements to the site of the flaw.