The performance advantage of square tube after calcium treatment requires not only high strength, but also good machining performance. For sulfur-containing square tube, sulfur can improve the machinability of steel, so the sulfide inclusion in square tube is the key to determine the quality of steel. Sulfur mainly exists in the form of MNs in the steel. The single MNS inclusion is light black strip. The inclusion with this morphology cuts off the continuity of the steel matrix and makes great differences in the anisotropic properties of the steel. Calcium treatment of molten steel can inhibit the formation of MNS inclusions and combine MNS with al20 CAS to form composite spindle inclusions. Such inclusions can improve the machinability of steel and avoid the adverse impact of MNS inclusions on the properties of steel.
High productivity of square tube: the efficiency of cold production of mechanical parts is very high, especially for parts with large batch. Cold production can be several times, several times or even hundreds of times higher than cutting. For example, the use of cold pin for automobile is twice higher than that of cutting. At present, cold pin automata is used to improve productivity. The productivity of table cooling automata is equivalent to that of 100 ordinary lathes or 10 shaft self-propelled machines.
San-Rafael.If the re inspection results are unqualified (including the items whose preliminary inspection results are unqualified and re inspection is not allowed), the supplier can submit them for acceptance one by one; Or re conduct heat treatment (the number of RE heat treatment shall not exceed times), and propose acceptance with a new batch.
After the square tube is cut into a single square tube, the head and root of each batch of square tube shall be subject to strict first inspection. The mechanical properties, chemical composition, fusion condition, surface quality of square tube and NDT shall be carried out to ensure that the pipe making process is qualified before it can be officially put into production.
.When we understand the causes of defects in the drawing process of q355b square tube, we should constantly improve the technology in the subsequent production process, so that we can reduce the occurrence of defects.
Cutting: 1 to be fast, no teeth, or whether the cutting line is flat, the starch taste of oil affects the quality of dishes. First choose to cut potatoes with less sharp bottom, so when you cut, it's easy to leave the corner of the side end.
Square pipe is an important type of square pipe, which has great similarities with seamless steel pipe, but it is different. Square pipe is of great use in square pipe, most manufacturers need to do this function, not only painting but also galvanizing. Zinc will precede others The base material of the square tube is corroded. If painting is not for you, it will cost you two money. If painting, it is recommended that you brush the zinc rich primer, because you brush other paints, it will corrode quickly, and then continue to corrode your zinc coating, you should brush the zinc rich primer before galvanizing
The test can be carried out under cold and hot conditions. If the test temperature is not specified the test shall be carried out under normal temperature, but not lower than - 10 ℃.
Material classification of spiral welded square pipe square pipe is divided into ordinary carbon steel square pipe and low alloy square pipe according to material. Ordinary carbon steel is divided into Q19 Q2 q23 SS400, 20# steel, 45# steel, etc; Low alloy steels are divided into q34 16Mn, St52-3, etc.
Cold formed hollow section steel (American Standard) for cold pressed Q345B square tube (national standard) structure carbon steel cold-formed circular section and pressure welded Q345B square tube and seamless Q345B square tube (European standard) non alloy fine grain cold formed welded hollow structural profile (Japanese standard) angle steel Q345B square tube for general structure galvanized q355b square tube for low pressure fluid transmission, Standard No.: gbt3091-2008. Representative materials: q235q235bq345b, etc. it is mainly used to transport water, gas, air, oil and water or steam. It is a special product manufacturing enterprise integrating R & D, and service. It has long been a professional square tube, square tube, seamless square tube galvanized square tube and galvanized tube. Its purpose is only limited to general low-pressure fluid.
Installation material list.Square tube is made of steel ingot or solid tube blank through perforation, and then made by hot rolling, cold rolling or cold drawing. Square pipe plays an important role in steel pipe industry.
After isothermal quenching, qq355b square tube will have excellent rolling fatigue characteristics and corrosion resistance. Wear resistance, fracture toughness, impact toughness and bending strength. Therefore, in the subsequent production and application, qq355b square tube will be used as the material of rolling mill flap ball screw. The qq355b square tube of case hardening steel also has the surface compressive stress characteristics obtained by heat treatment, and its application range is expected to be improved and expanded.
Before gas cutting, remove the dirt and grease on the steel surface, and leave a certain space below to facilitate the blowing out of slag. During gas cutting, the movement of the cutting torch shall be kept at a uniform speed. The cutting surface should be 2 ~ 5mm away from the tip of the flame core. If the distance is too close, the edge of the cut will melt, and if it is too far away, the cutting will be interrupted easily due to insufficient heat.
The covering shall be strong and durable to prevent decay and leakage caused by long-term sun and rain.
Create brilliance.Material classification: square pipe is divided into ordinary carbon steel square pipe and low alloy square pipe.
Stage (1978 & mdash; 1992)
Ordinary carbon steel is divided into Q19 Q2 q23 SS400, 45# steel, etc.
San-Rafael.The belt is sent to the metal flaw detector (or hydrostatic test) for internal flaw detection. If there are cracks, bubbles and other problems inside the steel pipe they will be detected. Steel pipes should be strictly selected manually after quality inspection. After the steel pipe is inspected, the number specification, production batch number, etc. shall be sprayed with paint. And hoisted into the warehouse by crane.
Soft blowing treatment of molten steel after calcium treatment can reduce residual inclusions in molten steel and better wrap MNS around al20 CAS and other cores.
The service life has a great impact on the isotropic performance of the square tube. The use of secondary refining technology (including vacuum refining, ESR and ladle powder spraying) can improve the purity of the square tube, especially reduce the content of harmful impurities in the square tube, which is beneficial to improve the performance.