Under the action of thermal stress because the initial temperature of the surface layer is lower than that of the heart and the shrinkage is greater than that of the heart, the heart is pulled. At the end of cooling, because the final cooling volume shrinkage of the heart cannot be carried out freely, the surface layer is compressed and the heart is pulled. That is, under the action of thermal stress, the surface of the workpiece is finally compressed and the center is pulled. This phenomenon is affected by factors such as cooling rate, material composition and heat treatment process. The faster the cooling rate, the higher the carbon content and alloy composition, the greater the uneven plastic deformation caused by thermal stress during cooling, and the greater the final residual stress. On the other hand, due to the change of microstructure during heat treatment, i.e. the transformation from austenite to martensite, the increase of specific volume will be accompanied by the expansion of workpiece volume, and each part of workpiece will undergo phase transformation successively, resulting in inconsistent volume growth and structural stress. The final result of the change of tissue stress is the tensile stress on the surface and the compressive stress in the center, which is just opposite to the thermal stress. The microstructure stress is related to the cooling rate, shape and chemical composition of the workpiece in the martensitic transformation zone. Frame line crackSan Pablo ,In order to strengthen the 'muscles and bones' of the bridge, the construction party specially paved two layers of reinforcement mesh before pouring cement. Miscellaneous scabGoris, Judged as failing.However, what we need to do now is to improve the production technology level of China&#;s production process of C-section steel, and step up the formulation of relevant industry standards and inspection standards. C-section steel manufacturers should keep close contact with truck manufacturers and communicate more. In this way, it is more conducive for C-section steel manufacturers to produce C-section steel products suitable for truck industry.→ I-beam can be processed into T-beam, and honeycomb beam can be combined to form various section forms, which greatly meets the needs of engineering design and manufacturing.

Alloy steel pipe is a new type of seamless steel pipe connection pipeline. The selection of pipeline connection pipeline, whether it is fire water system software, or pipeline, heat and national defense industrial pipeline system software of petrochemical pipeline system, alloy steel pipe stimulates important effects.Galvanized pipes shall be stored in dustproof to keep clean and new . As a professional manufacturer of galvanized pipe, we have produced galvanized pipe products for many years. Welcome friends who need to buy.The specification of pass design I-beam is expressed in cm of waist width. For example, the waist width of No. I-beam is. The types of I-beam include hot-rolled ordinary I-beam, light I-beam and wide parallel leg I-beam (H-beam). The waist width of hot-rolled ordinary I-beam in China is ~, expressed as No. ~ No., and the inclination of inner wall of leg is : The pass system of rolled I-beam includes direct pass system, cross pass system and mixed pass system. In addition I-beam can also adopt special rolling method.Trustworthy,I-beam can only be used for beam,San Pablo Cold drawn welded pipe manufacturer, while H-beam can be used for load-bearing column of structure.Key technical characteristics of alloy pipe Peak crack

I-beam is mainly divided into ordinary I-beam, light I-beam and wide flange I-beam. According to the height ratio of flange to web, medium and narrow flange I-beams. The specifications of the first two are -, that is, the corresponding height is -. At the same height, the light I-beam has narrow flange, thin web and light weight. Wide flange I-beam, also known as H-beam is characterized by two parallel legs and no inclination on the inner side of the legs. It belongs to economic section steel and is rolled on four high universal mill, so it is also called 'universal I-beam'. Ordinary I-beam and light I-beam have formed national standards.Let's see,The import and export order of I-beam is generally based on the specifications required in use after determining the corresponding carbon structure steel (or low alloy steel) steel grade. Except for the specification number,San Pablo Rectangular tube, I-beam has no specific composition and performance series.Are there many welded types of mesh produced? According to the welding type and overall improvement, the difference between the reinforcement mesh and the welded mesh is not particularly large. It is still due to the scattered quality of the southern city. From the perspective of development to the longitudinal and transverse interleaving devices of the reinforcement mesh, the bound or welded mesh has better application quality.Due to the relatively high and narrow section size of ordinary I-beam and light I-beam, the moment of inertia of the two main sleeves of the section is quite different, which makes it very limited in the scope of application. The use of I-beam shall be selected according to the requirements of design drawings.San Pablo , The small length of repair welding is mm; The raw material shall not exceed mm after grinding by welding edge.Last week, the billet in North China market showed a slight rebound trend. The billet quotation in Tangshan, the leading city, rose first and then stabilized in four trading days, with a strong wait-and-see atmosphere in the market. Affected by the almost stagnation of festival procurement, Tangshan billet fell by yuan during the Dragon Boat Festival holiday. On the first day after the festival,San Pablo How much is the price of DN80 galvanized pipe per meter, although the phase snail is still running at a low level, due to the small billet resources in the market, the steel mills unexpectedly rose, and the billet market rebounded. However, the steel plant has always maintained a cautious wait-and-see attitude to maintain stability.I-beam has wide flange, thin web, it is easy to assemble and combine into various components, which can save about % of the welding and riveting workload greatly accelerate the construction speed of the project and shorten the construction period.