1. It can be corroded with potion, but the efficiency is low and not environmentally friendly. 2. Silk screen printing can be used, which is not environmentally friendly and not wear-resistant. 3. Using a laser marking machine is the best method, with high efficiency and wear resistance. Moreover, stainless steel can also be colored with laser, such as W color, black, fantasy color, etc. It’s up to you.
For heat treatment of stainless steel pipes, oxidation-free continuous heat treatment furnaces with protective gas are commonly used abroad to perform intermediate heat treatment during the production process and final product heat treatment. Since a bright surface without oxidation can be obtained, the traditional Pickling process. The adoption of this heat treatment process not only improves the quality of steel pipes, but also overcomes the environmental pollution caused by pickling.
According to the current world development trend, bright continuous furnaces are basically divided into three types:
(1) Roller hearth bright heat treatment furnace. This type of furnace is suitable for heat treatment of large-sized and large-volume steel pipes, with an hourly output of more than 1.0 tons. The protective gases that can be used are high-purity hydrogen, decomposed ammonia and other protective gases. Can be equipped with a convection cooling system to cool the steel pipe faster.
(2) Mesh belt type bright heat treatment furnace. This type of furnace is suitable for small-diameter thin-walled precision steel pipes. The hourly output is about 0.3-1.0 tons. The length of the steel pipes can be processed up to 40 meters. It can also process capillary tubes in rolls.
(3) Muffle type bright heat treatment furnace. The steel pipe is installed on a continuous handle frame and heated in the muffle tube. It can process high-quality small-diameter thin-walled steel pipes at a lower cost, with an hourly output of about 0.3 tons or more.
Stainless steel welded pipe process technology - argon arc welding
Stainless steel welded pipe requires deep penetration, no oxide inclusions, the heat affected zone as small as possible, and tungsten inert gas protection Argon arc welding has good adaptability, high welding quality, and good penetration performance. Its products are widely used in chemical, nuclear, food and other industries.
The low welding speed is a shortcoming of argon arc welding. In order to increase the welding speed, various methods have been researched and developed abroad. Among them, the welding method of multi-electrode and multi-torch has been developed from single electrode and single torch and applied in production. In the 1970s, Germany first used multiple welding torches arranged in a straight line along the direction of the weld to form a long heat flow distribution and significantly increase the welding speed. Generally, argon arc welding with a three-electrode welding torch is used. The wall thickness of the welded steel pipe is S≥2mm. The welding speed is 3-4 times higher than that of a single welding torch, and the welding quality is also improved. The combination of argon arc welding and plasma welding can weld steel pipes with larger wall thickness. In addition, using 5-10% hydrogen in argon gas and using a high-frequency pulse welding power source can also increase the welding speed.
Multi-torch argon arc welding is suitable for welding austenitic and ferritic stainless steel pipes.
Stainless steel welded pipe process technology - high frequency welding
High frequency welding has been used in the production of carbon steel welded pipes for more than 40 years, but its use in welding stainless steel pipes is relatively new. technology. The economy of its production makes its products more widely used in the fields of architectural decoration, household appliances and mechanical structures.
High-frequency welding has a higher power supply and can achieve higher welding speeds for steel pipes of different materials, outer diameters and wall thicknesses. Compared with argon arc welding, it is more than 10 times the maximum welding speed. Therefore, the production of general-purpose stainless steel pipes has higher productivity.
Because of the high speed of high-frequency welding, it is difficult to remove burrs in welded pipes. At present, high-frequency welded stainless steel pipes are not accepted by the chemical and nuclear industries, which is one of the reasons.
From the perspective of welding materials, high-frequency welding can weld various types of austenitic stainless steel pipes. At the same time, the development of new steel types and the advancement of form welding methods have also successfully welded ferritic stainless steel AISI409 and other steel types.
Welded pipe process technology - combined welding technology
Various welding methods of stainless steel welded pipes have their own advantages and disadvantages. How to maximize strengths and avoid weaknesses and combine several welding methods to form a new welding process to meet people's requirements for stainless steel welded pipe quality and production efficiency is a new trend in the current development of stainless steel welded pipe technology.
After exploration and research in recent years, the combined welding process has made progress. The production of stainless steel welded pipes in Japan, France and other countries has mastered certain combined welding technology.
Combined welding methods include: argon arc welding plus plasma welding, high-frequency welding plus plasma welding, high-frequency preheating plus three-torch argon arc welding, and high-frequency preheating plus plasma plus argon arc welding. Combination welding can significantly increase the welding speed.
For combined welding steel pipes using high-frequency preheating, the weld quality is equivalent to conventional argon arc welding and plasma welding. The welding operation is simple and the entire welding system is easy to automate. This combination is easy to connect with existing high-frequency welding equipment and requires investment. Low cost and good benefits.
The influence of TIG welding activator on weld formation (1)
TIG welding has been widely used in production. It can obtain high-quality welds and is often used to weld non-ferrous metals. , stainless steel, ultra-high strength steel and other materials. However, TIG welding has shortcomings such as shallow penetration (≤3mm) and low welding efficiency. Thick plates require beveling for multi-pass welding. Although increasing the welding current can increase the penetration depth, the increase in weld width and molten pool volume is much greater than the increase in penetration depth.
The influence of TIG welding activator on weld formation (2)
The activated TIG welding method has attracted worldwide attention in recent years. This technology coats the surface of the weld with a layer of active flux (activator for short) before welding. Under the same welding specifications, compared with conventional TIG welding, the penetration depth can be greatly increased (the maximum 300%). For 8mm thick plate welding, a larger penetration depth or one penetration can be obtained at one time without beveling. For thin plates, the welding heat input can be reduced without changing the welding speed. Currently, A-TIG welding can be used to weld stainless steel, carbon steel, nickel-based alloys, titanium alloys and other materials. Compared with traditional TIG welding, A-TIG welding can greatly improve productivity, reduce production costs, and at the same time reduce welding deformation, which has very important application prospects. The key factor in A-TIG welding is the selection of active agent components. Currently, the commonly used active agent ingredients are mainly oxides, chlorides and fluorides. Different materials have different applicable active agent ingredients. However, due to the importance of this technology, the ingredients and formulas of active agents are subject to patent restrictions in both PWI and EWI, and are rarely reported in public publications.