Titanium tube welding process points
Titanium tube has a higher strength, good ductility and corrosion resistance, aerospace, shipbuilding, chemical applications more and more widely. To make the best use of titanium tubes, we must master the weldability. This article mainly expounds the titanium pipe welding process, which provides a useful reference for the future titanium pipe welding.
Welding material
Welding wire: ERTi-2; Welding method: GTAW (manual TIG welding)
Protection gas: Use argon gas with purity of 99.995% and water content of not more than 50Mg% m3, and apply argon gas protection to the weld pool and the area where the inner and outer surface temperatures of the welded joints are higher than 400 ℃.
2 welding preparation
(1) groove processing
Titanium tube cutting, the use of alumina grinding machine polished out of the groove, as shown below, processing groove does not allow the base material overheating discoloration.
(2) groove and wire cleaning
A. Bevel and both sides of the inner and outer surfaces within 50mm to clean up, cleaning procedures are as follows:
Polisher sandpaper polishing acetone cleaning.
After cleaning cannot be carried out directly to the welding operation, to be grooved face to dry before work. If left for more than 2 hours, it must be cleaned again or self-adhesive tape and plastic cloth level protection.
B. The wire is also wiped clean with acetone sponge and stored in a special wire box.
C. The operator must wear clean gloves during the welding process.
3 welding process specifications
(1) Welding specifications: the following table
(2) Welding should be selected within the scope of qualified process parameters small wire energy welding. The general control of 6 ~ 35KJ / cm, should adopt a small current, slow welding.
(3) The interlayer temperature shall not be higher than 200, to prevent the high temperature time is too long grain growth.
(4) In order to protect the surface of arc-closing arc after arc-breaking, the temperature of the welding point should be below 300, and the gas supply protection should be stopped after the timer reaches 15 ~ 60s according to the small to large diameter.
(5) Argon protection: Specific measures are as follows:
A. For DN greater than or equal to 450 pipe welding, the tube staff to wear gas masks, and guards on the back of the weld pool protection.
b. For DN less than 450 pipe or fixed mouth welding, the overall argon protection, the pipe surface within 150-300mm from the groove with a soluble paper seal, and then plug a group of soluble paper to prevent the pipe pressure is too large to seal soluble Paper damage, and then filled with argon gas will drain the tube. Pre-welding argon gas must be fully pre-filled with argon should be delayed, so that the cooling zone to fully cool the surface to prevent oxidation.
(6) Filler wire should continue with the protection of Argon during welding. Extinguishing wire shall not be immediately exposed to the atmosphere, should be deleted from the weld when the protection. If the wire is contaminated, oxidative discoloration, the pollution should be eliminated.
(7) No arc or test arc shall be applicable to the surface of the weldment; the arc crater shall be filled up during arc-closing, and the joints between layers of multi-layer welding shall be staggered from each other.
(8) Unless otherwise specified, each weld shall be continuously welded ones. If it is discontinued for any reason, it must be inspected after re-welding to confirm that there is no crack before welding can be continued.
(9) If tungsten is accidentally caught in the welding operation, the welding operation should be stopped, the tungsten point should be removed with a grinder, the end of the tungsten grade should be unsharpened, and the welding operation can be resumed after the requirements are met.
The above process points to ensure the normal titanium tube welding, but also to realize the quality of the titanium tube welding requirements.
Titanium tube has a higher strength, good ductility and corrosion resistance, aerospace, shipbuilding, chemical applications more and more widely. To make the best use of titanium tubes, we must master the weldability. This article mainly expounds the titanium pipe welding process, which provides a useful reference for the future titanium pipe welding.
Welding material
Welding wire: ERTi-2; Welding method: GTAW (manual TIG welding)
Protection gas: Use argon gas with purity of 99.995% and water content of not more than 50Mg% m3, and apply argon gas protection to the weld pool and the area where the inner and outer surface temperatures of the welded joints are higher than 400 ℃.
2 welding preparation
(1) groove processing
Titanium tube cutting, the use of alumina grinding machine polished out of the groove, as shown below, processing groove does not allow the base material overheating discoloration.
(2) groove and wire cleaning
A. Bevel and both sides of the inner and outer surfaces within 50mm to clean up, cleaning procedures are as follows:
Polisher sandpaper polishing acetone cleaning.
After cleaning cannot be carried out directly to the welding operation, to be grooved face to dry before work. If left for more than 2 hours, it must be cleaned again or self-adhesive tape and plastic cloth level protection.
B. The wire is also wiped clean with acetone sponge and stored in a special wire box.
C. The operator must wear clean gloves during the welding process.
3 welding process specifications
(1) Welding specifications: the following table
(2) Welding should be selected within the scope of qualified process parameters small wire energy welding. The general control of 6 ~ 35KJ / cm, should adopt a small current, slow welding.
(3) The interlayer temperature shall not be higher than 200, to prevent the high temperature time is too long grain growth.
(4) In order to protect the surface of arc-closing arc after arc-breaking, the temperature of the welding point should be below 300, and the gas supply protection should be stopped after the timer reaches 15 ~ 60s according to the small to large diameter.
(5) Argon protection: Specific measures are as follows:
A. For DN greater than or equal to 450 pipe welding, the tube staff to wear gas masks, and guards on the back of the weld pool protection.
b. For DN less than 450 pipe or fixed mouth welding, the overall argon protection, the pipe surface within 150-300mm from the groove with a soluble paper seal, and then plug a group of soluble paper to prevent the pipe pressure is too large to seal soluble Paper damage, and then filled with argon gas will drain the tube. Pre-welding argon gas must be fully pre-filled with argon should be delayed, so that the cooling zone to fully cool the surface to prevent oxidation.
(6) Filler wire should continue with the protection of Argon during welding. Extinguishing wire shall not be immediately exposed to the atmosphere, should be deleted from the weld when the protection. If the wire is contaminated, oxidative discoloration, the pollution should be eliminated.
(7) No arc or test arc shall be applicable to the surface of the weldment; the arc crater shall be filled up during arc-closing, and the joints between layers of multi-layer welding shall be staggered from each other.
(8) Unless otherwise specified, each weld shall be continuously welded ones. If it is discontinued for any reason, it must be inspected after re-welding to confirm that there is no crack before welding can be continued.
(9) If tungsten is accidentally caught in the welding operation, the welding operation should be stopped, the tungsten point should be removed with a grinder, the end of the tungsten grade should be unsharpened, and the welding operation can be resumed after the requirements are met.
The above process points to ensure the normal titanium tube welding, but also to realize the quality of the titanium tube welding requirements.
