Spiral welded pipe production management and price analysis

Spiral welded pipe (SSAW) production management and price analysis:

1. Production and management
The production of spiral welded steel pipes can reflect the advantages of high quality and efficiency. The production volume of one spiral welded pipe unit is equivalent to 5-8 straight seam welded pipe (LSAW/ERW pipe) equipment. How to make multiple pipe rolling equipment production lines meet the same production standards, that is, produce according to unified production process specifications and quality assurance systems to meet the welding quality Requirements and pipe fabrication grades would be a tedious job.

Multi-head production potential increases the amount of engineering management and quality supervision. Multiple straight seam pipe coiling units and corresponding welding equipment. Differences in the operating skills, quality awareness, distribution points and control procedures of their operators will bring many difficulties in production management, planning progress, inspection and acceptance, delivery coordination, etc. , it is easy to cause confusion in management and coordination and quality evasion between manufacturers and construction units.

2. Quality assurance
According to the provisions of spiral welded pipe production standards, the main inspection/control items of spiral welded steel pipes include:

Overall dimensions: steel pipe outer diameter, wall thickness, ovality, curvature, pipe end verticality,
Length appearance quality: weld reinforcement, misalignment, steel pipe surface, delamination, inclusions, weld defect determination
chemical composition
Tensile test of welded joints
Hydrostatic pressure test
Acid etching test
Non-destructive inspection

Generally, spiral welded pipe units use online continuous inspection to ensure the welding quality of the welds. This is another important feature that distinguishes spiral welded pipe production from straight seam welded pipe production. Continuous inspection is beneficial to the monitoring of welding defects, the stability of welding quality, and the guarantee of welding grade.

Due to the limitations of the production process, it is extremely difficult to achieve continuous and uninterrupted inspection of straight seam welded pipes. This will increase the probability of welding hazards and quality problems, and even affect the overall reliability of pipeline operations in the future.

3. Production qualification
Spiral welded pipe manufacturers should hold an industrial product production license issued by the state. The license system requires that manufacturers of spiral welded pipes must first pass the review and assessment of an authoritative certification agency recognized by the state, have corresponding production means and inspection equipment, and have a good and effective quality assurance system. The products should meet the requirements of national standards and quality specifications. , the license will be issued after confirmation by the National Industrial Product Production License Office. Therefore, spiral welded pipe manufacturers have relatively complete quality assurance systems and quality control operating procedures.

4. Price analysis
Due to the high material technical performance and production technology requirements of hot-rolled coils, on the one hand, there are fewer domestic manufacturers that meet the standards than steel plate manufacturers. On the other hand, their production technology and quality level determine that their market price is also higher than that of hot-rolled coils. Rolled steel plate. This is the main reason why the market price of spiral welded pipes is higher than that of straight seam welded pipes. Regarding the composition of steel pipe sales prices, material prices are the dominant or even decisive factor.

Carefully examine the price difference between spiral welded pipes and straight seam welded pipes. The price of spiral welded pipes is slightly higher than that of straight seam welded pipes due to the price difference in the main production materials. However, steel pipe production is only a part of the project. If factors such as the overall quality of the project and the comprehensive cost of the project are taken into consideration, spiral welded pipes still have overall advantages.

5. Fixed length and price

The yield rate of producing fixed-length pipes is much lower than that of ordinary length pipes, so it is reasonable for manufacturers to request a price increase. The price increase range varies from company to company, but is generally about 10% above the base price. The fixed length should be within the usual length range and should be a certain fixed length required in the contract. However, it is impossible to cut an absolute fixed length in actual operations, so the standard stipulates the allowable positive deviation value for the fixed length. If there are no provisions for length deviation and cutting allowance in the standard, it should be negotiated between the supplier and the buyer and specified in the contract. The double-length scale is the same as the fixed-length length, which will significantly reduce the yield rate of the manufacturer. Therefore, it is reasonable for the manufacturer to propose a price increase, and the price increase range is basically the same as the fixed-length length.

Tips: ASTM A53 covers seamless and welded steel pipe with nominal wall thickness. The surface condition is usually black and hot-dipped galvanized. ASTM A53 is produced mainly for pressure and mechanical applications, and is also used for transport of steam, water, gas line pipes.

Read more: Seamless vs Welded Pipe or Carbon steel vs Stainless steel