CN-122007692-A - Anti-oxidation circumferential seam welding method for stainless steel water tank liner

Abstract

The invention discloses an anti-oxidation circumferential seam welding method for a stainless steel water tank liner, which belongs to the technical field of shielding gas welding and comprises the steps of accurate butt joint of a liner barrel body and a seal head, shielding gas filling, shielding gas monitoring, concentration control and circumferential seam welding; according to the invention, high-precision butt joint of the inner container body and the sealing head is realized, cracks are effectively prevented from being generated in the welding process, argon is introduced from the bottom of the inner container before welding, air is naturally discharged from the air outlet at the top by utilizing the characteristic that the density of the argon is greater than that of the air, the concentration of the argon in the inner container is ensured to be more than 99.5%, the back surface oxidation of a welding seam is prevented, the opening of the air charging flow and the opening of the air outlet valve are dynamically and slightly adjusted during welding by real-time data feedback of the gas concentration detector and the pressure detector, the high-quality and non-oxidation welding of the circular seam of the inner container of the stainless steel water tank is realized while the concentration of the argon is maintained, and the internal pressure of the inner container is prevented from being too high due to welding heat input.

Inventors

• ZHANG GUOQING
• OUYANG YUGUANG
• LI HANYAO

Assignees

• 广州纬华节能设备有限公司

Dates

Publication Date

20260512

Application Date

20260302

Claims (2)

1. 1. The stainless steel water tank liner comprises a liner barrel body and an end socket, and the oxidation-resistant circumferential weld welding method of the stainless steel water tank liner is characterized by comprising the following steps of: s1, accurately butting the liner barrel body and the seal head, namely rounding the seal head through a tool, and guiding the liner barrel body in the process to realize the accurate butting of the liner barrel body and the seal head and prevent cracks from generating during welding; S2, filling the protective gas, namely erecting the butted liner, closing other openings, opening only the gas outlets at the bottom and the top of the liner respectively, and filling the welding protective gas from the gas inlets at the bottom of the liner to ensure that air is discharged from the gas outlet at the top of the liner, so that the welding seam of the liner of the stainless steel water tank is prevented from oxidizing with oxygen in the air during welding; S3, monitoring and controlling the concentration of the protective gas, namely respectively installing a pressure detector near a butt joint of the inner container and installing a gas concentration detector at a top gas outlet, and monitoring the pressure in the inner container and the concentration of the protective gas in real time when the gas concentration detector detects that the concentration of the protective gas at the top gas outlet of the inner container is 99.5%, adjusting a control valve installed at the top gas outlet of the inner container to enable the gas outlet to be smaller until the gas outlet is closed, and simultaneously adjusting the gas filling flow; S4, continuously filling protective gas at low flow rate under the monitoring of a pressure detector and a gas concentration detector during circumferential seam welding, ensuring the concentration of the protective gas to be not lower than 99.5%, preventing oxidation phenomenon during welding, controlling the gas outlet to slightly give out gas, realizing real-time pressure relief, preventing the pressure overload in the liner caused by high temperature of welding, and finally realizing the anti-oxidation circumferential seam welding of the liner of the stainless steel water tank.
2. 2. The shielding gas of claim 1, wherein the shielding gas is argon.

Description

Anti-oxidation circumferential seam welding method for stainless steel water tank liner Technical Field The invention relates to the technical field of shielding gas welding, in particular to an anti-oxidation girth welding method for a stainless steel water tank liner. Background When stainless steel is welded, under the condition of lack of protection, high temperature easily causes oxidation reaction of a stainless steel welding line and oxygen in air to cause corrosion resistance to be reduced, and the serious degradation of the performance makes a welding line area very easy to be a corrosion break in subsequent use, rust and leakage easily start from the welding line in the future, and the corrosion break is a fatal defect for a stainless steel water tank liner in a high-temperature and high-pressure state for a long time and must be prevented by a strict welding protection process. The existing stainless steel water tank liner circumferential seam welding has two processes, namely, one process is that the seal head is inserted into the liner, the seal head and the liner form an inserting welding joint, two problems exist after the seal head and the liner are welded, a gap exists between the seal head inside the liner and the liner, the gap can lead to gap corrosion, in addition, the back of a welding seam is not protected by gas during welding, the corrosion resistance of the water tank liner can be reduced due to oxidation of the back of the welding seam, the second process is that the seal head is in butt joint with the liner to form a butt joint, and a lining strip is additionally arranged during assembly of the seal head and the liner, so that on one hand, the assembly precision of the liner and the seal head is ensured, on the other hand, the lining strip is tightly matched with the welding joint during welding, and the oxidation of the back of the welding seam during welding is reduced. In the method, gaps between the inner liner of the liner and the girth weld can cause gap corrosion, and oxidation of the back surface of the weld is not thoroughly solved. In order to solve the problem of oxidization of the back surface of a welding line during welding, the prior art is generally matched with a special protection cover, high-purity protection gas (inert gases such as argon, helium and the like or carbon dioxide and mixed gas) is filled into the cover in advance to drive air in the cover, and the protection cover slides synchronously along with the position of a back molten pool during welding and is precisely linked with the front welding operation, so that the back surface of the welding line is effectively protected, and oxidization of the molten pool and a heat affected zone is avoided. The protective gas welding technology has obvious applicability defects that the conventional following back protective gas cover is difficult to move along with a welding track in a sealing way in real time because the welding back is not a smooth plane, so that protective gas cannot cover and synchronously follow a welding pool effectively, the back of a welding line is protected discontinuously to form an oxidation risk area, if the protective gas is directly filled into the liner, the filled protective gas is easy to circulate with external air because of the semi-closed structural characteristic of the protective gas, a stable and compact protective gas curtain is difficult to form in the welding area, the welding oxidation prevention effect cannot be ensured, and if the protective gas is continuously filled at a large flow rate in the welding process for isolating the air of the welding back, the welding cost is increased, the defects of concave root parts and the like of the welding line are caused by air flow impact, and the welding quality is seriously influenced. Disclosure of Invention The invention aims to provide an anti-oxidation circumferential seam welding method for a stainless steel water tank liner, which solves the technical problems. An anti-oxidation circumferential seam welding method for a stainless steel water tank liner is used for welding the stainless steel water tank liner and is characterized by comprising the following steps of: s1, accurately butting the liner barrel body and the seal head, namely rounding the seal head through a tool, and guiding the liner barrel body in the process to realize the accurate butting of the liner barrel body and the seal head and prevent cracks from generating during welding; S2, filling the protective gas, namely erecting the butted liner, closing other openings, opening only the gas outlets at the bottom and the top of the liner respectively, and filling the welding protective gas from the gas inlets at the bottom of the liner to ensure that air is discharged from the gas outlet at the top of the liner, so that the welding seam of the liner of the stainless steel water tank is prevented from oxidizing with oxygen in the air during welding; S3,