Introduction: Seamless steel pipe is perforated by the whole round steel, and the steel pipe without weld on the surface is called seamless steel pipe.

Categories:
Cross section: steel pipe without seams on the surface;
Production methods: hot rolled pipe, cold rolled pipe, cold drawn pipe, extruded pipe, pipe jacking, etc.
Material: ordinary and high-quality carbon structural steel (Q215-A ~ Q275-A and No. 10 ~ 50 steel), low alloy steel (09MnV, 16Mn, etc.), alloy steel, stainless acid-resistant steel, etc.
Uses: general purpose (for water, gas pipelines and structural parts, mechanical parts) and special (for boilers, geological exploration, bearings, acid resistance, etc.) two categories.

Application:
1, the general purpose seamless steel pipe is rolled by ordinary carbon structural steel, low alloy structural steel or alloy structural steel, the maximum output, mainly used as a pipeline or structural parts for transporting fluids.
2, according to different uses divided into three types of supply:
A. Supply according to chemical composition and mechanical properties;
b, according to mechanical performance supply;
c, according to water pressure test supply. Steel pipes supplied according to class a and b, such as those used to withstand liquid pressure, should also be hydraulically tested.
3, the special purpose of seamless pipe with boiler seamless pipe, chemical power, geological seamless pipe and petroleum seamless pipe and so on.
The seamless steel pipe has a hollow cross-section and is widely used as a pipeline for conveying fluids, such as pipelines for conveying oil, natural gas, gas, water and some solid materials. Compared with solid steel such as round steel, steel pipe is light in weight while bending and torsional strength is the same, and it is an economic cross-section steel.
Widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipe, automobile transmission shaft, bicycle frame and steel scaffolding used in construction and other steel pipe manufacturing ring parts, can improve material utilization, simplify the manufacturing process, save materials and processing hours, has been widely used to manufacture steel pipe.

Production process:
① The main production process of hot rolled seamless steel pipe (main inspection process) :
Preparation and inspection of tube billet → heating of tube billet → perforation → Rolling of tube → reheating of steel tube → Sizing (reducing) → Heat treatment → straightening of finished tube → finishing → inspection (non-destructive, physical and chemical, table inspection) → storage
② Cold rolled (drawn) seamless steel pipe main production process:
Blank preparation → pickling lubrication → Cold rolling (drawing) → Heat treatment → straightening → finishing → inspection

Generally used seamless steel pipe is made of 10, 20, 30, 35, 45 and other high-quality carbon bonded steel 16Mn, 5MnV and other low alloy structural steel or 40Cr, 30CrMnSi, 45Mn2, 40MnB and other bonded steel hot rolled or cold rolled. Seamless pipes made of low carbon steel such as 10 and 20 are mainly used for fluid transport pipelines. 45, 40Cr and other medium carbon steel seamless pipe to manufacture mechanical parts, such as cars, tractor parts. Generally use seamless steel pipe to ensure the strength and flattening test. Hot-rolled steel pipes are delivered in hot-rolled or heat-treated condition; Delivered cold rolled in heat-treated condition.