Square tube has good machinability, good cold deformation plasticity and weldability; In addition, but it has quite high strength and wear resistance especially when water quenching; However, temper brittleness and overheating during heat treatment.
At present researchers at home and abroad have carried out experimental discussion on the anti adhesion of square tube surface. So far, there is no systematic and perfect theory to guide the preparation of anti adhesion inner surface of pipeline there is still a lack of research on surface adhesion, and there is a lack of operable and low-cost inner surface preparation technology of square pipe. In terms of solid surface adhesion mechanism, based on the solid-liquid interface adhesion work theory and smooth solid surface model, this paper analyzes the spreading process on machined rough surface, studies the dynamic movement characteristics of solid-liquid vapor phase line, directly analyzes the adhesion process, and establishes a line spreading model based on small system energy, such as warehouses, but it is not suitable for moving components such as wheels. At this time, people often use the plastic theory. The research of the plastic theory can be traced back to 1914. In 1975, the European Design Association formulated D plastic design code, which is mainly used for plane beams under static load and bending stress For the frame structure with stress, the requirements are as follows:% 26sigma; B% 26sigma;% 26zeta;% 26ge;% 26delta;% 26ge; 15% for high-rise buildings, more detailed calculation is required. In the case of plastic design, the allowable stress is usually calculated according to the safety factor that the allowable stress is not less than the dynamic load and multiplied by the allowable stress. In the case of bending of an axis, the formula a = w can be used Using plasticity instead of calculated strength can improve the bearing capacity of members by 14%.
Effective treatment of square tube coating & ldquo; Surface defense line & rdquo; Surface technology and measures square tube coating is used as the back course & ldquo; Surface defense line & rdquo; The surface treatment technologies and measures can be carried out on the basis of other surface treatment technologies or processes. Here's the & ldquo; Surface treatment before coating & rdquo; It refers to all treatment measures for preparation for coating or joint protection with coating. Therefore, the surface treatment before coating is also called coating surface pretreatment.
The cut-off position shall match the construction and site conditions, draw the determined position and mark the cut-off line with a meter ruler or other measuring tools.
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.
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.
Mechanical properties of seamless q355b square tube: tensile strength & sigma; b (MPa)：≥ 980 yield strength & sigma; s (MPa)：≥ 835 elongation & Delta; 5(%)：≥ 12 reduction of area & psi; (%)：≥ 40 impact absorption energy (impact value) (aku2j): & Ge; 39 the products produced by the more complex technology are exquisite. At present, Fangguan is highly praised by the public in the market. What is important is that there is a good guarantee in terms of quality. Therefore, whether Fangguan can obtain such a high market evaluation depends on the complex technology of Fangguan.
retailer.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.
The standard number of spiral square pipe (standard of the Ministry of petroleum) for low pressure transmission is syt5037-2008. The representative materials are q235bq345b and other carbon steel materials. It is mainly used for low-pressure transmission of water, oil, natural gas, heating and other pipelines.
In the heat exchange planning of metallurgy, petrochemical and other occupations, there are various forms of heat exchangers, but the conventional heat exchangers have many disadvantages, such as poor heat exchange, difficult cleaning, large dust thermal resistance and so on, which can not meet the needs of production customers. The square tube heat exchanger based on square tube throat has the advantages of excellent heat exchange, easy cleaning, small dust thermal resistance and compact structure.
The square tube is formed by external control or internal control roller.
Excellent service.There are several kinds of color q355b square tubes: high temperature oxidation method, chemical oxidation method, electrochemical oxidation method, ion implantation method and gas phase cracking method.
The strength, plasticity and hardness discussed above in fatigue Q235B are the indicators of the mechanical properties of metals under static load. In fact, many machine parts work under cyclic load, under which fatigue will occur.
Q355b square pipe for mining fluid transportation, Standard No.: gbt14291-2000. The representative material is Q235 grade B steel, which is mainly used for coal mine air pressure, drainage and vertical shaft gas drainage straight seam q355b square pipe.
Fot.It seems that preheating the q355b square tube can avoid a lot of problems, and there will be a better guarantee that the q355b square tube itself is a quality problem.
In case of doubt about the strength of solid q355b square tube, it can be based on tb10426 & mdash; 200 the compressive strength of q355b square tube on the surface of the structure is indirectly measured by the post loading method. The measurement should be carried out at the age of about 56 days, and the measured average strength is required to be not lower than the design value or the specified value. When the requirements are not met, the core drilling sampling method can be used for verification.
Among them, q355b square tube is divided into process & mdash& mdash; Arc welded square pipe, resistance welded square pipe (high frequency and low frequency), gas welded square pipe and furnace welded square pipe are divided by weld & mdash& mdash; Straight seam welded square pipe, spiral welded square pipe.