Hardness hardness is a pointer to measure the hardness and softness of metal materials. At present, the hardness method is commonly used to measure the hardness in production. It uses the indenter with fixed geometry to measure the hardness value of the metal material surface tested under fixed load according to the degree of hardness.Principle of cold drawing strengthening: the lattice defects of steel increase during plastic deformation, and the serious distortion of defect lattice will hinder the progress and slip of lattice, so the yield point of steel increases and the plasticity and toughness decrease. Due to the internal stress in plastic deformation, the modulus of steel decreases. The cold drawn reinforcement is stored at room temperature for ~ d or heated to ~ ℃ and maintained for a fixed time. This process is called aging treatment.Kumen,The standard quantity of combustible and nonflammable square pipes is gbt- (gbt-). The representative material is l-l pipeline steel. Professional square pipes, seamless square pipes, galvanized square pipes and galvanized pipes are of high quality and low price. They are fire-resistant, waterproof, high temperature resistant, durable, safe and reliable. They are mainly used to transport combustible and nonflammable fluids with high requirements.Square tube production most square tube processing is square tube pressure processing, resulting in plastic deformation of the processed steel (billet,KumenQ235A galvanized pipe, ingot, etc.). According to the square tube processing temperature, the square tube can be divided into cold processing and hot processing. The main processing of square tube includes: rolling: the gap (various shapes) between the square tube metal blank and the rotating roll , because of the compression of the roll the material section is reduced and the length is increased. This is a common production method for producing square tubes. It is mainly used to produce square tube profiles, plates and tubes. It is divided into cold rolling and hot rolling.Khujaobod,Main uses of square tube: square tube is mainly used in tap water engineering, petrochemical industry, chemical industry, electric power industry, agricultural irrigation and urban construction. It is one of the key products developed.The strength, plasticity and angle discussed later are the machine function indicators of metal under static load. In practice, many mechanical machines are under repeated load and the whole opportunity is tired in this environment.Pig iron refers to the product made by smelting iron ore in blast furnace. It is mainly used for steelmaking and square casting. Put the cast pig iron in the melting furnace to obtain cast iron (liquid), and cast the liquid cast iron into a cast square pipe. This kind of cast iron is called cast iron.

Oil drilling pipe (yb-) is a square pipe used for internal or external thickening at both ends of oil drilling. Steel pipes are divided into turning wire and non turning wire. Turning wire pipe is connected with joint, and non turning wire pipe is connected with tool joint by butt welding.The iron filings and burrs on the cutting section shall be completely removed with a file or appropriate tools to prevent the iron filings and burrs from scratching the rubber O-ring and other accessories when connecting another part.Generally, chemical and electrolytic methods are usedinvestment,QB square tube is a product appeared in recent years, which mainly has strict tolerance and roughness for the dimensions of inner hole and outer wall. Production process classification of large-diameter qb square tube large-diameter qb square tube is divided into hot-rolled seamless square tube,KumenSpecification table of 4-point galvanized pipe, cold drawn seamless square tube, seamless square tube and qb square tube according to production process. Among them, qb square tube is divided into: (a) by process & mdash& mdash; Arc welded square pipe, resistance welded square pipe (high frequency and low frequency), # steel, # steel, etc; Low alloy steels are divided into q Mn, Q,Kumen40 thick galvanized square pipe, St-, etc.Welding is a synthetic gradient material, mechanical and physical properties between base metals.The appearance of fake and inferior square tubes often has pitting. Pockmarked surface is an irregular uneven defect on the surface of square lead pipe due to serious wear of rolling groove. Due to the pursuit of profit by fake and shoddy square tube manufacturers, the rolling of rolling groove often exceeds the standard.

Change to square pipe: generally, the strip steel is unpacked, leveled, crimped and welded to form a round pipe then rolled into a square pipe from the round pipe, and then cut into the required length. Stage ( & mdash; )Welcome calls ,High quality steel (P & le; .%, S & le; .%)All seamless qb square tubes shall be tested for mechanical properties. Mechanical property tests are mainly divided into two categories: tensile test and hardness test.Comprehensive classification ordinary steel A. carbon structural steel: (a) Q (b) Q (b); (c) Q( C)； (d) Q( B)； (e) Q.KumenThere are many processing technologies for square tubes. I won't introduce the specific processing technology here. We only know about the processing technology of each other's tubes. We may have insufficient understanding of its heating technology. Next, I'll give you a detailed introduction to the heating technology of the lower tubes.Purpose of square tube the purpose of square tube includes construction, machinery, steel construction and other projects, shipbuilding, solar power generation support, steel structure engineering, compression, bending and shear, the strength is also divided into tensile strength, compressive strength, flexural strength and shear strength. There is often a certain between various strengths. Generally, tensile strength is used as the basic strength indicator. Precision pipe is a seamless pipe with high dimensional accuracy and good surface finish for mechanical structure and hydraulic equipment. The selection of precision seamless mechanical structure or hydraulic equipment can greatly save machining hours, improve material rate and improve product quality. Seamless pipe is rolled in the annular pass composed of variable cross-section circular hole groove and fixed conical plug. Cold drawing is usually carried out on single chain or double chain cold drawing machine. This method is to put the heated pipe blank in a closed cylinder, and the perforated rod and rod move to extrude the part from the smaller die hole. This method can produce steel pipe with smaller diameter.