Brinell hardness， Rockwell hardness and Vickers hardness are commonly used.
2Stainless steel qb square pipe for fluid transportation， Standard No.: gbt-. The representative materials are Cr crni crni cr crninb， crnimo， etc.， which are mainly used to transport low-pressure corrosive media.
pDuring the pushing process of spot welding and repair welding elbows，Square tube there will be thinning，Galvanized square pipe manufacturing equipmentHow to do independent research and development so manufacturers usually use thick spot pipes. If thin raw materials are used， the products produced must be unqualified. Generally， there are about wires thinned. If the technology is not good or the drawn pipe is used， the thickness is significantly lower than the standard.
Square tubes shall be stored with supports， products and tens of millions of products for you to choose. You can professionally sell square tubes， square rectangular tubes， seamless square tubes， galvanized square tubes and galvanized tubes. The transaction safety of galvanized tubes is guaranteed， and they are at a certain distance from the ground to ensure the ventilation of square tubes.
OMatagalpaTherefore，Square tube QA is usually not preheated. However， when the plate is very thick， it should be preheated because it cools quickly. Once # steel was cracked by J welding. If the plate thickness is more than mm， there is a great risk of not preheating.
CkApplication: it is widely used in machinery， construction， metallurgy， agricultural vehicles， agricultural greenhouses， railways highway guardrails， container frames，Square tube square tubes raw materials， i.e. strip coils，Galvanized square pipe manufacturing equipmentHow to do independent research and development welding wires and fluxes. It must undergo strict physical and chemical inspection before being put into operation.
Sample length L & asymp; D (D is the outer diameter of the pipe). When the outer diameter is large， the length l shall not exceed mm. When the outer diameter is less than mm， l = mm.
Shot blasting is often used to clean the surface of castings or strengthen the surface of square tubes.
gClassification of square tube steel is iron carbon alloy with carbon content of square tube between .% - %. In order to ensure its toughness and plasticity， the carbon content generally does not exceed %. In addition to iron and carbon， the main elements of steel also include silicon， manganese， phosphorus， etc. There are various classifications of steel and square tubes，Galvanized pipe_ Galvanized square pipe_ Seamless steel pipe_ Square tube - Wuxi Jiahang showing a variety of different colors. Chemical oxidation method is to form various film colors in a specific solution at temperature and time; Because of the law & rdquo; More S & le; .%)
JA fixed thickness oxide film is formed， but to maintain the color of the product， the reference electrode must be used. Electrochemical method is to form the color of chloride film with fixed thickness in specific electrolyte at temperature， voltage and time. This process is mature and widely used. Ion implantation method is to vaporize ions in vacuum and deposit them on the surface of qb square tube， such as watch case on the market. The golden color of watch strap adopts this process technology， which is suitable for mass production. The process of gas phase cracking is more complex and less used in industry. Square tube has long been widely used in mechanical industry. When the square pipe is cut automatically， when the square pipe is hoisted to the gas cutting platform， the distance difference between the two ends of one side of the pipe and the guide rail shall be adjusted within mm. During semi-automatic cutting， the guide rail shall be placed on the plane of the cut pipe， and then the cutting machine shall be placed on the guide rail gently.
DPromise and keep promiseThe difference between qb square tube and QA is that there are fewer impurities s and P and better low-temperature impact performance. From the welding point of view， when the impurity elements in the base metal are less， it is good for welding hot crack.
yDAfter 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.
From the perspective of production， we should give full play to the productivity of production equipment and reduce the consumption of fuel and equipment on the basis of meeting the size and performance requirements of qb square tube. Therefore， the temperature of no open forging and final forging is a comprehensive technical and economic problem. If qualified qb square tubes can be obtained in the temperature range of the vehicle， reasonable process procedures should be selected from an economic point of view. Obviously， the higher the temperature， the easier the forging and the higher the productivity， but the greater the fuel consumption and the loss of the heating furnace; We should consider these two aspects and make a reasonable choice.
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 - ℃.
Create brilliancexChemical polishing: less investment in processing equipment， high speed， high efficiency and good durability. Its defects are poor brightness， gas overflow， demand for ventilation equipment and difficult heating. It is suitable for processing small batch of disordered parts and products with low brightness demand for small parts.
NCold drawn or cold rolled precision square tube (gb-) is a cold drawn or cold rolled precision square tube with high dimensional accuracy and good surface finish for mechanical structure and hydraulic equipment. The selection of precision square mechanical structure or hydraulic equipment can greatly save machining hours， low-pressure or high-pressure square pipes， with high requirements.
mAll seamless qb square tubes shall be tested for mechanical properties. Mechanical property tests are mainly divided into two categories: tensile test and hardness test.
gKThe welded joints of square pipes are subject to on-line continuous ultrasonic automatic flaw detector to ensure the NDT coverage of spiral welds. If there are defects， it will automatically alarm and spray marks. The production will adjust the process parameters at any time to eliminate the defects in time.
After perforation， the round tube blank is successively rolled by cross rolling continuous rolling or rolling. Take off the pipe after sizing. The conical drill bit of the sizing machine rotates into the steel embryo at high speed to form a steel pipe. The inner diameter of the steel pipe is determined by the outer diameter length of the sizing machine bit. After sizing， the steel pipe enters the cooling tower for water spray cooling. After cooling， the steel pipe will be straightened. After straightening， the steel pipe is sent to the gold pipe by belt