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Tianjin Yuantai Derun Pipe Manufacturing Group Co., Ltd., established in March 2002, is the biggest manufacturer specializing in  ERW square&rectangular tube/pipe, hollow section structure pipe, galvanized pipe and spiral welding pipe in China. Annual output reaches 5 million tons.Yuantai Derun has 59 production lines of black ERW pipe, 10 production lines of galvanized pipe and 3 production lines of spiral welding pipe. Square pipe from 20*20*1mm to 500*500*40mm, rectangular pipe from 20*30*1.2mm to 400*600*40mm,  welded pipe from 2”—60” can be manufactured. Yuantai Derun can manufacture square rectangular pipes as per the standards of ASTM A500, JIS G3466, EN10219, DIN2240, BS1387, AS1163.

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January 1993

Key team members of Yuantai Derun group began technical job in Tianjin Daqiuzhuang tube factory.

June 2002

Tianjin Yuantai Industry & Trade Co., Ltd. was founded, specialize in square, rectangular hollow steel pipe, hot galvanized welded (hot dip galvanized) square tube, the registered capital is USD 10 million.

May 2004

One of Yuantai subsidiaries Tangshan Lituo Steel Tube Co., Ltd. was established, specialize in square rectangular straight welded hollow steel pipe, registered capital is USD 10 million.

April 2005

Yuantai Steel Square Pipe Co. Ltd. was established, specialize in square welding hollow steel tube and galvanized tube, the registered is USD 2 million.

March 2010

Tianjin Yuantai Runxiang commercial trade company was established, specialize in strip steel trade, galvanized pipe agent, etc., the registered capital is USD 2 million.

March 2010

Tianjin Yuantai Derun pipe manufacturing group Co. Ltd. was formally established, marking that the production of high-frequency welded black, galvanized square pipe, spiral welded pipe, pipe logistics and pipe trade as one of the large-scale joint enterprise Yuantai Derun group was formally established, the group registered capital is USD 20 million.

March 2010

Tianjin Yuantai Derun Investment Co., Ltd. was formally established, specialize in steel pipe industry chain,lower industry mergers and acquisitions and industrial real estate development, the registered capital is USD 2 million.

August 2013

Tianjin Derun Runfeng pipe manufacturing Co. Ltd was established, specialize in hot galvanized (hot galvanizing) processing business, the registered capital is USD 8 million.

March 2015

Tianjin Yuantai Yuanda anti-corrosion insulation pipe Co., Ltd. was established, specialize in spiral welded pipe production and sales, the registered capital is USD 2 million.

August 2015

Tangshan Yuantai Derun Pipe Co., Ltd. was established, specialize in steel strip, steel pipe trade, registered capital is USD 1 million.

March 2016

Tianjin Yuantai Derun International Trade Co., Ltd was established,mainly engaged in international import and export business for Yuantai Group, registered capital is USD 2 million.

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What are the defects prone to occur in the welding process of spiral welded steel pipe?-news-TIANJIN YUANTAI DERUN PIPE MANUFACTURING GROUP CO., LTD-
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What are the defects prone to occur in the welding process of spiral welded steel pipe?
What are the defects prone to occur in the welding process of spiral welded steel pipe?

1. Involvement of welding slag: Welding slag is a part of the welding slag remaining in the weld metal.

2. Poor penetration

The metal overlap of the inner and outer welds is not enough, and sometimes there is no penetration. This situation is called insufficient penetration.

3. Undercut

The undercut is a V-shaped groove on the edge of the weld along the center line of the weld. The undercut is produced when the welding speed, current, voltage, and other conditions are not appropriate. Among them, the welding speed is too high to be more suitable than the current It is more likely to cause undercut defects of spiral welded steel pipe.


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4. Bubbles

Most of the bubbles occur in the center of the weld bead. The main reason is that hydrogen is still hidden in the welded metal in the form of bubbles. The measure to eliminate this defect is to first remove the rust, oil, moisture, and moisture of the welding wire and weld, secondly, the flux must be dried well to remove moisture.

5. Sulfur cracking

Sulfur cracking is a crack caused by sulfur. When welding a plate with a strong sulfur segregation zone, the sulfide in the sulfur segregation zone enters the weld metal. The reason is that the sulfur segregation zone contains iron sulfide and steel with a low melting point. hydrogen gas is present.

6. Hot crack

In the submerged arc welding of spiral welded steel pipe, thermal cracks can be generated in the weld bead. In order to eliminate such cracks, backing plates are usually installed at the arc starting and extinguishing places, and when the coil butt welding is completed, the spiral welded steel pipe can be reversed and the weld into the stitch weld.