Measures to Improve the Precision of Seamless Steel Tubes

Posted by chase Liu on May 19th, 2023

In order to ensure the quality and size requirements of the joints, the joints of seamless steel pipes and stainless steel must be machined, which can be processed by lathes or portable rotary bevel milling cutters. According to the on-site construction conditions, due to geographical restrictions and maintenance needs, a portable rotary beveling machine is used to process the bevel. In the construction of water supply pipelines, ensuring the construction quality is the top priority of the entire project, and the hygiene, safety and quality of raw materials are the key to the safe and reliable operation of the pipeline network. In actual construction, attention should be paid to raw materials, anti-corrosion form, thickness of anti-corrosion layer, interface treatment, etc. Carry out construction operations in strict accordance with design requirements and national standards, improve technical standards, ensure construction quality, and ensure safe water supply. The control of seamless steel pipe is a difficult point in the production of steel pipe

Measures to improve the precision of seamless steel pipes mainly include the following aspects:

1. Heating tube billet

Heating should be uniform, do not heat up or cool down quickly. Each temperature rise and fall should be kept steady and slow, and the maximum temperature rise and fall should not exceed 30°C.

2. Centering roller

Determine whether the centering roller is installed in place, and adjust the center, opening angle and opening size of the relevant core-holding roller to make it consistent with each action. The center of the core roll should be on the pass line.

3. Rolling center line

Make sure that the rolling centerline of the piercing machine is consistent with the centerline of the piercing trolley, and avoid "upward rolling" or "downward rolling", so as to ensure that the tube blank is evenly stressed during piercing.

4. Scroll tool

Worn plugs, guide plates, rollers and other rolling tools should be replaced in time.

5. Installation of rolling tools

The center of the roll pitch and lead must be on the pass line. Ensure that the center line of guide distance and roll distance is on the center line of piercing and rolling, that is, the upper and lower roll distances are equal, and the left and right guide distances are equal.

6. Perforated ejector pin

The perforated ejector pin is generally a thick-walled pipe with an outer diameter of φ 108mm-φ 114mm, and the seamless steel pipe requires ≥25mm, and the seamless steel pipe is uniform.

7. Rolling mill mandrel

The mandrel should be a thick-walled seamless steel pipe, and the mandrel with a smaller size can be replaced by a solid blank. The uniform thick-walled pipe and solid blank of seamless steel pipe can greatly reduce the probability of mandrel bending deformation, and effectively improve the precision of seamless steel pipe.

8. Mandrel accuracy

The slenderness of the mandrel is relatively large. Generally, the outer diameter of the mandrel is turned first, and then the welding is broken, or the long material is directly turned into shape. The external machining accuracy of the mandrel should be controlled within 0.1mm, and the straightness deviation of the mandrel should not exceed 5mm. When welding, a finished pin is inserted between the two mandrels for positioning to prevent excessive deviation of the overall straightness caused by welding.

The seamless pipe refers to the steel pipe which is perforated by the whole round steel and has no weld seam on the surface. The seamless pipe has the size of schedule 40 pipe. It is mainly used as petroleum geological drilling pipe, octg casing, cracking pipe for petrochemical industry, boiler pipe, bearing pipe and high-precision structural steel pipe for automobile, tractor and aviation.