The chemical composition of cold-rolled ribbed strip is the same as that of hot-rolled smooth round strip. It is rolled at room temperature with hot-rolled smooth disc strip， which is called cold rolling. Due to the reorganization of steel crystal structure by cold rolling process
The chemical composition of cold-rolled ribbed strip is the same as that of hot-rolled smooth round strip. It is rolled at room temperature with hot-rolled smooth disc strip high tensile strength (LL， ll， ll， etc.) is obtained， which has poor ductility and cannot be welded. If there are double-sided ribs and three-sided ribs，Products Show the specification allows LL to be used as stirrup. The design value of strength is limited to n / mm?.
2Seamless pipe has a high position in steel pipe，Wichito13crmo4-5 alloy pipeCommon performanceysis and there are many large factors. The main usage has accounted for more than %， which is applicable to all walks of life. Seamless pipe factories in China are widely produced. At present， the number of factories in China is also increasing every year， which is determined by the nature and production conditions of seamless pipe. The common production processes and processes are more complex.
mNew OrleansClassification introduction
General welded pipe: General welded pipe is used to transport low-pressure fluid. It is made of qa， qa and QA steel. It can also be made of other mild steel that is easy to weld. Water pressure， zigzag， flattening and other tests shall be carried out for steel pipes， and there are certain requirements for surface quality. Generally， the delivery length is -m，Products Show and steel pipe can be divided into threaded and non threaded according to the way of pipe end.
HIn SalahThe advantages of shiny galvanized pipe are:
YpWelded thin-walled pipe: mainly used for making furniture， toys lamps， thin-walled tubes made of stainless steel strip are widely used， such as high furniture， decoration， fence and so on.
Material requirements
Galvanized pipes are designed to maintain high enough corrosion resistance.
tI-beam is a long strip steel with groove section， which belongs to carbon structural steel for construction and machinery. It is a section steel with complex section， and its section shape is groove shape. China&#;s imports of I-beams are greater than its exports. The main producing areas are Tangshan Iron and steel， Baotou Iron and steel， Shangang，Products Show huangte， Maanshan Iron and steel，Wichito13crmo4-5 alloy pipeCommon performanceysis Xuanhua Iron and steel， Japan iron and steel， etc.
MRecently， the price of zinc has been falling continuously. The key reason lies in the soft skin of galvanized pipe consumption and the slow start of production and marketing rate of manufacturing industries in the middle and lower reaches after the Spring Festival. The disadvantage of zinc price has long been far beyond the level of cyclical factors. The main performance of no prosperity in the hot season is whether the market situation in the off peak season will become a more worried problem in the galvanized pipe sales market.
KGood qualityDuring the heating and cooling process of structural welded pipe workpiece， due to the inconsistent cooling speed and time of surface layer and core layer， the temperature difference will be formed， resulting in uneven volume expansion and contraction， resulting in stress，Reinforcement, galvanized pipe, seamless pipe, welded pipe, alloy pipe, I-beam-Shandong Kaiwen metal material Co., Ltd namely thermal stress. Under the action of thermal stress， the starting temperature of the surface layer is lower than that of the core layer， and the shrinkage is greater than that of the core layer， making the core layer stretch. At the end of cooling， the surface layer is compressed and the core is stretched because the cooling volume contraction of the core cannot be carried out freely. That is， under the action of thermal stress， the surface of the workpiece is compressed and the core is pulled.
mRNext， let&#;s introduce the operation steps of roll adjustment during roll change. First of all， we must replace the specification and model of the welded pipe manufacturer. Generally， replace the complete set of rolls. The adjustment process of the rolls is as follows: first， draw an axis from the channel of the generator set to the import and export with stainless steel wire for adjustment， so that the holes of each frame plate are on the same axis and the bottom line of forming ethics meets the technical standards.
Check whether the manufacturer&#;s qualification， business license， organization code certificate， tax registration certificate， production and operation license and other qualification materials are complete. Look at the case， investigate the supplier&#;s performance and the projects served in the past. Whether there is a self built logistics fleet or not， choosing a service provider with a self built logistics fleet can reduce the transportation cost， and more importantly， ensure the timeliness of delivery. After sales service， whether there is a sound and reliable after-sales service guarantee system， and timely solve quality problems in arrival acceptance and subsequent use. Check whether the quality assurance materials such as product quality certificate， material specification and warranty are complete. Check the appearance of the welded pipe， the surface is smooth and flat， the weld is dense， without burr， oil stain， corrosion， extrusion deformation and flat cross section. Use a micrometer to check whether the outer diameter and wall thickness of the welded pipe meet the requirements， bend the welded pipe for degrees， and there is no crack at the bend.
Defect detection of seamless pipe
Installation materialsu The reinforcement on both sides of the inverted beam extends into the beam respectively， and the anchorage length of the reinforcement is the same as that of the reinforcement， without hook.
TMethods of exerting efficiency in application of C-section steel
Keep the combustion supporting gas and use it reasonably to avoid fracture of the welding interface. Problems in the welding of steel wire mesh skeleton composite pipe are common， which should be prevented or solved.
gNew OrleansThe product can withstand any range of operating temperature.
cD It has a thick and dense pure zinc layer covered on the steel surface， which can prevent the steel substrate from touching with any corrosion solution and maintain the steel substrate from corrosion. In general atmosphere， the surface of zinc layer forms a thin and dense zinc oxide layer， which is difficult to dissolve in water， so it plays a certain maintenance effect on steel matrix. If zinc oxide and other components in the atmosphere form insoluble zinc salts， the anti-corrosion effect is more ideal.
The zinc coating is thick， uniform and non porous， and the corrosion resistance is excellent;