Causes and preventive measures of stainless steel welded pipe defects

- Jan 04, 2021-

Stainless steel welded pipes will have some defects in the welding process. The defects of stainless steel welded pipes will lead to stress concentration, reduce bearing capacity, shorten service life and even cause brittle fracture. General technical regulations stipulate that cracks, incomplete penetration, unfused and surface slag are not allowed; defects such as undercut, internal slag and pores cannot exceed certain allowable values, and must be thoroughly removed and welded for excessive defects. Make up. The causes, hazards and preventive measures of welding defects of common stainless steel welded pipes are briefly described below.


  First, the weld size does not meet the requirements


  The weld seam size does not meet the requirements mainly refers to the weld height and residual height difference, the weld width and width difference, the wrong side amount, the post-weld deformation and other dimensions that do not meet the standard requirements. The weld seam is uneven, uneven and deformed. Great. The weld width is inconsistent, in addition to causing the weld bead to be unsightly, it also affects the bond strength between the weld and the base metal; if the weld height is too large, causing stress concentration, and the weld is lower than the base metal, there is not enough Joint strength; if the wrong side and deformation are too large, the force transmission will be distorted and stress will be concentrated, resulting in a decrease in strength.


  Causes: improperly angled or unblind edge of stainless steel welded pipe and uneven assembly gap; unreasonable selection of welding process parameters; low skill level of welders.


  Precautionary measures: select the appropriate groove angle and assembly clearance; improve the assembly quality; select the appropriate welding process parameters; improve the welder's operating technology level.


  Second, undercut


  Due to incorrect selection of welding process parameters or incorrect operation process, the grooves or depressions formed by burning along the base material of the weld toe are called undercuts. The undercut not only weakens the strength of the welded joint of the welded pipe, but also causes cracks due to stress concentration.


  The cause is: the current is too large, the arc is too long, the angle of the electrode is not correct, and the method of transporting the strip is improper.


  Preventive measures: When welding arc welding, it is necessary to select the appropriate welding current and welding speed, the arc can not be pulled too long, the angle of the electrode should be appropriate, and the method of transportation should be correct.


Product Description
A steel pipe made of a single piece of metal with no seams on its surface is called a seamless steel pipe. According to the production method, the seamless pipe is divided into a hot rolled pipe, a cold rolled pipe, a cold drawn pipe, an extruded pipe, a top pipe, and the like. According to the shape of the section, the seamless steel tube is divided into two types: a circular shape and a special shape. The shaped tube has a plurality of complicated shapes such as a square shape, an elliptical shape, a triangular shape, a hexagonal shape, a melon shape, a star shape, and a winged tube. The maximum diameter is 650mm and the minimum diameter is 0.3mm. Depending on the application, there are thick-walled tubes and thin-walled tubes. Seamless steel pipes are mainly used for petroleum geological drilling pipes, cracking pipes for petrochemicals, boiler tubes, bearing tubes, and high-precision structural steel tubes for automobiles, tractors, and aviation.
Specification
Cold rolled decorative stainless steel pipe
Welded steel pipe referred to as welded pipe, is made of steel plate or steel strip after the unit and mold after the welding of the steel pipe. Stainless steel decorative pipe is also called stainless steel welded steel pipe, commonly used steel or steel strip after the unit and mold crimping welding made of steel pipe. Welding steel tube production process is simple, production efficiency is high, variety specification is more, equipment is less, but general strength is lower than seamless steel tube.
Standard
JIS, AISI, ASTM, GB, DIN
Type
Tubes & Pipes
Certification
ISO
Length
1000mm-12000mm
Diameter
SCH
Place of Origin
Shandong, China
Brand Name
SDtaigang
Application
Building construction Certification:ISO
Product name
wholesale steel prices SS 304 316 316L Stainless Steel Round Tube Welded Thin Wall Steel Pipe
Model
201/304/304L/316L
Edge
Mill / Slit Edge
Surface Treatment
Mirror polished
Application range
Building construction, Machine manufacturing Kitchen utensils
MOQ
1TON
Brand
SDtaigang
Common sense of stainless steel can be known, stainless steel seamless tube is made of steel ingots or solid tube blanks through perforation to make capillary, and then hot rolled, cold rolled or cold drawn. It is widely used in the manufacture of structural parts and mechanical parts, such as petroleum drill rods, automobile drive shafts, bicycle frames, and steel scaffolding used in building construction. When selecting stainless steel seamless pipes, you should pay attention to the following aspects:
First, measure the size. Relevant standards have requirements for the length, curvature, out-of-roundness and uneven wall thickness of the steel pipe, as well as the shape of the tip. The steel pipe can be placed on a flat ground, and the steel pipe can be rolled to observe the size and change of the gap between the steel pipe and the ground. Both ends of a qualified seamless steel pipe should be perpendicular to the axis, and the cut should be free of burrs.
Grade
C
Si
Mn
P
S
Ni
Cr
Mo
Cu
SUS304
≤0.08
≤1.00
≤2.00
≤0.045
≤0.030
8.0-10.0
18/20
--
--
SUS301
≤0.15
≤1.00
≤2.00
≤0.045
≤0.030
6.0-8.0
16/18
--
--
SUS201
≤0.15
≤0.75
≤5.5/7.5
≤0.06
≤0.030
0.8-1.2
16/18
--
--
SUS430
≤0.12
≤0.750
≤1.00
≤0.040
≤0.030
≤0.60
16/18
--
--
SUS443
≤0.015
≤1.00
≤1.00
≤0.04
≤0.030
--
≥20
--
≤0.3
SUS310S
≤0.1
≤1.50
≤2.00
≤0.045
≤0.03
19-22
24-26
--

SUS316L
≤0.07
≤1.00
≤2.00
≤0.045
≤0.30
10-14
16-18.5
2.0-3.0
--
Packing & Delivery
Packing Details : Export standard package,bundled or be required.
The inner size of container is below:
20ft GP: 5.8m(length) x 2.13m(width) x 2.18m(high)
40ft GP: 11.8m(length) x 2.13m(width) x 2.18m(high)
40ft HG: 11.8m(length) x 2.13m(width) x 2.72m(high)
Delivery Details : 7-15 days,or according to the order quantity or upon negotiation

Individual package of single pipes
Company Profile

Cangzhou Steel Pipe Group (CSPG)Co.,Ltd.

No.92 JieFang East Road ,Cangzhou City, Hebei,P.R.China.

CSPG  has more than eighteen years history company which located in Lecong Iron and Steel World, a well-known steel distribution center in China, with superior geographical position and convenient water and land transportation. 


We are a direct-selling manufacturer specializing in the research and development of spiral steel pipes, steel spiral pipes, anti-corrosion steel pipes inside and outside. Since its inception, the company has been guided by a brand-new thinking of steel pipe product market based on the business philosophy of honesty, pragmatism and knowledge-seeking.

 

product process
Certifications
FAQ
Q: Are you a manufacturer or trading company?
A: We are a specialized manufacturer.

Q: How about the delivery terms?
A: 1. Payment: T/T, Western Union, Paypal, 30% deposit in advance and balance before delivery.
2. Min. Order Quantity: 100KG, or as required.
3. Transportation: By express (DHL,TNT,FedEx),air,sea,and train.

Q: How about discount?
A: Price is based on products and order quantity.

Q: Do you accept sample order?
A: Yes sure, please contact us for details.

Q: How about your after-sales service?
A: As a professional steel exporter, we offer promote technology support for all problems and questions.
Besides, we accept goods return or replace for quality problem.

Q: How does your company control the quality?
A: Quality first. In order to guarantee high quality for our products,