What is a hot rolled seamless steel pipe?

Hot rolled seamless steel tube is a kind of seamless steel tube, according to the production method to divide. Compared with cold rolling, cold rolling is carried out at room temperature and hot rolling is carried out at recrystallization temperature. Seamless steel tubes are named relative to welded steel tubes, which are usually made from round steel perforated and reprocessed, and welded steel tubes are usually made from steel plates welded in different ways. The diameter of hot rolled seamless steel pipe is usually above 38mm. Small diameter seamless steel tubes can be obtained by cold rolling or cold drawing.

Hot rolled seamless steel tube is manufactured by hot rolling technology. As the name implies, the rolled parts have high temperature, small deformation resistance and large deformation can be realized. Take steel plate rolling as an example, the thickness of continuous casting slab is generally about 230mm, and the final thickness is 1~20mm after rough rolling and finishing rolling. At the same time, because the thickness ratio of the steel plate is small, the dimensional accuracy is relatively low, it is not easy to produce shape problems.

Hot rolled seamless steel tube process:

The deformation process of hot rolled seamless steel tube production base can be summarized into three stages: perforation, extension and finishing.

General process flow of hot rolled seamless steel pipe: round bar → heating → piercing → three roll cross rolling, rolling or extrusion → parting → sizing (or reducing) → cooling → parison tube → straightening → hydrostatic test (or flaw detection) → marking → storage.

The billet is sent to the heating furnace at a temperature of about 1200 ℃. Hydrogen or acetylene fuel. The temperature control of the furnace is very important. The air pipe wheel is threaded and the pressure is released after punching. One of the most common punches is the tapered roller punch, which has high production efficiency, good product quality, large punching expansion and can wear a variety of steels. After piercing, the round pipe is cross rolled, rolled or extruded by three rollers.

Pipe sizing after extrusion. The sizing machine enters the billet punch by the high-speed rotary taper drill to form the steel pipe. The inner diameter of the steel pipe is determined by the length of the outer diameter of the sizing machine bit. The sizing steel pipe enters the cooling tower through water spray cooling, and the cooled steel pipe needs to be straightened. It is sent out by the conveying pipe through the straightening metal detector (or hydrostatic test) for internal defects. Internal problems such as cracks and bubbles will be detected.

The steel pipe quality inspection shall be strictly selected manually. For the quality supervision and inspection of steel pipes, paint shall be applied on the quantity, size and production batch. Take the cable car to the warehouse.

Hot rolled seamless pipe blank requirements:

The requirements of hot rolled seamless tube for tube blank are related to the variety, application and piercing method of the tube. The quality requirements for general steel pipes can be relaxed, but the quality requirements for important application pipes and high alloy steel pipes must be strict. The perforation method with good stress condition or small deformation may have slightly lower requirements on the surface and internal quality of the pipe without affecting the performance of the pipe. For the double roll rotary perforation with unfavorable stress, if the perforation deformation is large, there are strict requirements for the surface and internal quality of the pipe. In a word, the technical conditions of steel pipes are determined on the basis of ensuring the quality and smooth production process, and change with different perforation methods and with the improvement of the technical conditions of steel.

For example, the requirements of the general automatic pipe winding machine are as follows:

(1) Deviation of pipe diameter Dp in Table 1. Bending of any part of pipe ≤6mm/m, cutting slope of pipe end ≤ 6-8mm, flattening of pipe end ≤8%Dp;

(2) There is no crack, wrinkle, scar, scale layer, folding, non-metallic inclusion and residual shrinkage cavity on the surface of the tube. Small grooves, pitting, ears, and both ears that are more than 0.5mm in height or depth are not allowed. Pipe defects with a depth greater than 0.05Dp were cleaned;

(3) Low power lens barrel: ≥1 grade residual shrinkage, bubbles, peeling, white spots and cracks are not allowed. For common carbon structure billets, looseness ≤3, central porosity ≤3, segregation ≤3, subcutaneous bubbles ≤2.

Advantages of hot rolled seamless steel pipe:

It can destroy the ingot structure, refine the steel grain, eliminate the structural defects, make the steel structure compact and improve the mechanical properties. This improvement is mainly reflected in the rolling direction, so that the steel is no longer isotropic; Bubbles, cracks and looseness are formed during pouring, and welding can also be carried out under high temperature and high pressure.

Application of hot rolled seamless steel pipe:

1. Building: it is mainly used for pipeline transportation at the bottom. It is used for pumping groundwater and transporting boiler hot water during building.

2. Machinery: used for machining, bearing sleeve, machining of mechanical parts, etc.

3. Electrical: fluid flow pipelines for gas transmission and hydropower generation.

4. Others: Antistatic tubes for wind power generation.

WORKSHOP EQUIPMENT

PACKAGE DELIVERY 20ft GP:5898mm(Length)x2352mm(Width)x2393mm(High)   24-26CBM

40ft GP:12032mm(Length)x2352mm(Width)x2393mm(High)   54CBM

40ft HC:12032mm(Length)x2352mm(Width)x2698mm(High)    68CBM

In bundle,plastic bags,thin film,wooden pallet,standard seaworthy export packing or as customer demands