Stainless steel welded steel pipe manufacturing approach

Stainless steel welded steel pipe thermal correction measures

Welded stainless steel thermal correction measures to popularize abroad with maintenance of gas-free oxidation for thermal processor furnace, the middle of the heat produced in the course of correction measures and the final product thermal correction measures, can get the light surface oxidation, and then set aside the traditional pickling process. The thermal processor technology adoption, both to improve the quality of the steel pipe, inhibited pickling the state of pollution.

According to the trend of the world at that time commenced, the light continuous furnace basically divided into three types:

Type light thermal processor (1) roller hearth furnace. This furnace together for large size, large amounts of the amount of steel pipe hot processor-hour production of more than 1.0 tons. Can be utilized to maintain gas of high purity hydrogen, differentiation, ammonia and other maintenance of gas. Can be equipped with a convection cooling system in order to faster cooling of steel pipe.

(2) network with light thermal processor furnace. This furnace is suitable for small-diameter thin-walled precision steel tubes, the hourly production of about 0.3-1.0 t, renew, steel pipe lengths up to 40 meters, you can also processor into the volume of the capillary.

(3) the Muffle light thermal processor furnace. Steel pipe installed in the continuous heating shelves, operating in the muffle tube, high-quality small-diameter thin-walled steel pipe at a lower cost processor, the hourly output of about 0.3 tons.

Stainless steel weld monitoring technology skills - welding

Stainless steel welded pipe requires deep penetration, free of oxide and mixed and do can be as small heat-affected zone melting, argon arc welding of tungsten inert gas to maintain a good adaptability, high welding quality, good penetration function, and its products in the chemical made throughout the nuclear industry and food industry use.

Welding speed is not the TIG lack of studying abroad opened up a variety of methods to improve the welding speed. One of the single-electrode single torch on using multi-electrode welding torch welding techniques in producing them. Germany in the 1970s first straight-line display multiple welding torch along the weld tendency to form the elongated shape of the heat flux distribution clearly increase the welding speed. The popular three-electrode arc welding torch, welding pipe wall thickness S ≥ 2mm, welding increased by 3-4 times faster than a single torch, welding quality can be improved. The combination of argon arc welding and plasma welding can weld a greater wall thickness steel pipe, in addition, 5-10% hydrogen in argon, using high-frequency pulse welding power, welding speed.

More welding torch argon arc welding of austenitic and ferritic stainless steel welded steel type used.

Stainless steel weld monitoring technology skills - high frequency welding

High-frequency welding for carbon steel welded pipe produced once before 40 years of history, but for welding stainless steel welded pipe is a relatively new skill. Its economy, produced its products for more throughout the architectural decoration, household appliances and mechanical structure range.

The high-frequency welding with more electrical power, substandard material, outside diameter and wall thickness of steel pipe can be arrived at high welding speed. Compared with the argon arc is more than 10 times the highest welding speed. Therefore, produced the popular use of stainless steel welded pipe has a higher production rate.

Because of the high speed of high frequency welded to the pipe within the burr removal hard. At that time, the high-frequency welding of stainless steel welded steel pipe for the chemical industry, nuclear industry is not yet accepted, and this is one of its announcement.

From the welding material, high frequency welding of austenitic stainless steel welding of various types of welded steel pipe. Also, the opening of the new steel and shaping the progress of welding techniques, has also succeeded in welding steels of the ferritic stainless steel AISI409.

Weld monitoring technology skills - welding skills together

All kinds of stainless steel pipe welding techniques have their respective advantages and lack of. The Ruo weaknesses, several welding techniques to be the combination to form a new welding process, contentment, and the quality of stainless steel welded pipe and produce efficiency, is the launching of a new trend when the stainless steel pipe skills.

Through in recent years to explore study, the combination of the welding process has been made to carry out, Japan, France and other countries of stainless steel welded pipe produced to have a grasp of certain combination of welding skills.

The combination of welding practice: argon arc plus plasma welding, high frequency welding and plasma welding, high-frequency warm-up plus three torch argon arc, the high-frequency preheat plasma and argon arc welding. The combination of welding to improve the welding speed is very clear. Welded steel pipe weld quality using a combination of high-frequency preheating with conventional arc welding, plasma welding quite simple welding operations, the entire welding system is easy to complete automation, this combination is easy to be connected with the existing high-frequency welding equipment, investment capital money, good benefits.

TIG welding surfactant shape of the weld (1)

Have made throughout the use of TIG welding produced in, it can obtain high quality welds, commonly used to weld non-ferrous metals, stainless steel, ultra-high strength steel and other materials. What, then TIG welding existence of the melt depth (≤ 3mm), and a defective welding efficiency, multi-pass welding on heavy plate demand groove. Although make penetration add to increase the welding current, but the magnitude of the weld width and weld pool volume to add to Hongyuan penetration to add margin.

TIG welding of the active agent of the weld forming (2)

The activity of the TIG welding method in recent years aroused within the limitations of the world pay attention. This skill is coated with a layer of active flux before welding, the weld surface (referred to as the active agent), under the same welding specifications, compared with the conventional TIG welding, you can greatly improve penetration (up to 300 %). Groove of 8mm thick plate welding can not open once the larger penetration depth, or a penetration, reduce the heat input on the sheet without changing the welding speed circumstances. A-TIG welding can be used for welding stainless steel, carbon steel, nickel-based alloys and titanium alloys and other materials. Compared with the conventional TIG welding, the A-TIG welding can greatly improve the producing rate, reduce the producing cost, can also reduce the welding deformation, with the very first use prospects. The key elements of the A-TIG welding is the matching of the active agent composition. Commonly used primary surfactant composition of the oxides, chlorides and fluorides, substandard materials, the composition of the active agent in combination substandard. What, then, due to the primary of this art, the composition and formulation of the active agent in the PWI and EWI have * rarely reported in the open publications. Studying for A-TIG welding was the primary focus in the study of the mechanism of surfactant results and activity of welding two aspects of the study of the application of skills.

TIG welding of the active agent of the weld forming (3)

At home and abroad to open up and use of active agents first of three types: oxide, fluoride and chloride. By the PWI in the early development of the active agent for titanium welding oxides and chloride-based What, then chloride toxicity, bad luck in the performance and use. Foreign welding stainless steel, carbon steel, such as the use of active agents with an oxide-based, while on the welding of titanium alloy active agent bound to the fluoride ingredient.

TIG welding of the active agent of the weld forming (4)

Single component of the active agent forming of stainless steel weld:

(1) coated with SiO2 weld of the active agent, followed by the addition of the silica coating amount, the weld bead width gradually narrower crater longer narrows change the deep. The rear of the weld I high active agent in the coating and uncoated live * then at the weld metal accumulation, all active agents in forming the results of the consequences of SiO2 on the weld. (2) active agent NaF, the Cr2O3 Butt Road forming the impact is unclear. Followed by the addition of the coating amount, the weld width changes are not large crater there is no clear change. Compared with the non-active agent of the weld, the weld bead width there is no clear change in the crater larger than the active agent to. (3) followed by the addition of the TiO2 coating amount, the appearance of the weld is little change in the crater did not clearly change the active agents are similar.

However, the composition of the weld surface is smooth manners, no undercut, forming better than the active agent of the weld. (4) the active agent the CaF2 Butt Road, forming a greater impact. Followed by the addition of CaF2 coating, weld shape variation, changed little crater, and little change in the weld width. Follow CaF2 amount of added defects such as undercut. (5), the deep penetration effect on the active agent, the five active agents can be added weld melt, followed by the addition of the coating amount, the penetration depth also echoed add. What, then when the coating amount is arrived at must be worth penetration add arrived saturated, and then add the amount of coating penetration worse.

TIG welding of the active agent of the weld forming (5)

Improve elders TANDEM high speed and high efficiency double wire MIG / MAG welding skills

The process can be welded carbon steel, low alloy steel, stainless steel, aluminum and other metal materials, is a fast, efficient, and improve the use throughout the elders welding skills.

High-speed welding and high deposition rate welding is the back soldering skills expand the tendency of MIG / MAG double-wire high-speed and efficient welding is one of the hot, it made more and more throughout the use of industrial production

TANDEM twin-wire welding affair

TANDEM twin wire welding system consists of two welders, two wire feeder and a torch, such as composition, use of automation plane or welding robots supporting. Two wire feeder wire feeding tube through the two taken to distinguish between the two wires to the conductive mouth of the torch in the two self-dual arc melting, the formation of a molten pool.

TANDEM twin wire welding process characteristics

1, high-function welder, 100% duty cycle when the welding current of 1000A, 1500A pulse current;

Digital pulse power, programmable, joins a PC, printer;

3, each wire specification parameters can be set independently in terms of material, the diameter of divergent samples;

4, each wire of the wire feed speed up to 30m/min;

5, Meng progress Deposited efficiency and welding speed;

6, when you add in the deposition efficiency, the confrontation between the lower heat input;

Same arc droplet transfer controlled;

8, small welding deformation;

9, little splash;

10, weld data monitoring and management;

11, the use of standard gas, gas consumption less;

12, the use of the limitations of widely produced high