Ibb12m galvani
San-RafaelHow 
HerediaDN25 gaNow in many construction projects, we can see the shadow of q355b square tube,IbbSteel galvanized square pipe, because q355b square tube is quite hard in hardness, and the performance and quality of deformation, stamping, which is also the guarantee of mechanical properties. Based on the above, it is very important to test the hardness of q355b square tube.
Evaluation of test results after the test, the bending deformation of the sample is qualified if there is no crack or crack. The squash test rating square pipe produced by square pipe factory has been widely used. Of course, the current situation is inseparable from the strict control of square pipe factory in technology, which makes the development of steel pipe make a lot of contributions. Let's look at the specific purpose of the lower tube.
Ibb.Strength refers to the performance of metal materials under static load (excessive plastic deformation or fracture). Since the action modes of load include tension, compression, bending and shear, the strength is also divided into tensile strength, compressive strength, flexural strength and shear strength. There is often a certain between various strengths. Generally, tensile strength is used as the basic strength indicator. Appropriate sites and warehouses shall be selected. The sites or warehouses for storing steel pipes shall be in clean and unobstructed places, away from factories and mines that produce harmful gas or dust. Weeds and sundries shall be removed on the site to keep the steel pipe clean; In the warehouse, it is not allowed to stack with acid, alkali, salt, cement and other materials that are corrosive to the steel pipe. Different types of steel pipes shall be stacked separately to prevent confusion and corrosion; Large section steel, rail, steel plate, large-diameter steel pipe, forging, etc. can be stacked in the open air; Small and medium-sized section steel,IbbDN65 galvanized round pipe, wire rod, reinforcement, steel wire and steel wire rope can be stored in a well ventilated shed, steel sheets, steel strips, silicon steel sheets, or thin-walled steel pipes, all kinds of cold-rolled and cold drawn steel pipes and high and corrosive metal products can be stored in the warehouse; The warehouse shall be selected according to geographical conditions, and generally adopts ordinary closed warehouse, that is, the warehouse with roof, enclosure,IbbStandard Specification for galvanized square pipe, tight doors and windows and ventilation devices; The warehouse is required to pay attention to ventilation in sunny days, close and damp proof in rainy days, and often maintain a suitable storage environment. The principle of reasonable stacking and first in first stacking is to stack according to varieties and specifications under the condition of stable stacking and ensuring safety. Materials of different varieties shall be stacked separately to prevent confusion and mutual corrosion; It is forbidden to store articles that have corrosive effect on steel pipes near the stacking position; The bottom of the stack shall be padded high, firm and flat to prevent the material from moisture or deformation; The same kind of materials shall be stacked according to the warehousing order, so as to facilitate the implementation of the principle of first in, first out; The section steel stacked in the open air must be provided with wooden mats or strip stones. The stacking surface is slightly inclined to facilitate drainage. Pay attention to the straightness of the material placement to prevent bending and deformation; The stacking height shall not exceed 2m for manual operation, 5m for mechanical operation, and 5m for stacking width; A fixed channel shall be reserved between stacks, generally 0.5m and the access channel is generally 5 ~ om depending on the size of materials and transportation machinery; The bottom of the stack shall be padded up. If the warehouse is cement floor, it can be padded up by 0.1M; If it is muddy ground, it must be padded 0.2 ~ 0.5m high. If it is an open site, the cement ground shall be padded with O & middot; 3～O· 5 m, 0.5 ~ 0.7 m higher than the sand and mud surface, the angle steel and channel steel shall be stacked in the open air, and the I-beam shall be placed vertically. The i-groove surface of the steel pipe shall not face up to avoid ponding and rust. The packaging and protective layer of the protective materials shall be coated with agent or other plating and packaging before leaving the factory, which is an important measure to prevent material corrosion. Attention shall be paid to protection during transportation, loading and unloading and shall not be damaged, The storage period of materials can be extended, the warehouse shall be kept clean and the maintenance of materials shall be strengthened. Before warehousing, materials shall be prevented from being drenched or mixed with impurities. Materials that have been drenched or contaminated shall be wiped according to their properties, such as steel wire brush for high hardness and cloth, cotton and other materials for low hardness; The materials shall be regularly after warehousing. If there is corrosion, the corrosion layer shall be removed; Generally the steel pipe surface does not need to be coated with oil after being cleaned, but for high-quality steel, alloy steel sheet, thin-walled pipe alloy steel pipe, etc., rectangular tubes all kinds of square tubes, seamless square tubes, galvanized square tubes and galvanized tubes have been recognized by the majority of customers for a long time. There are more and more counterfeit products on the market. In order to prevent being deceived when you are in square tubes, you need to know some knowledge about how to judge the authenticity of square tubes: & ldquo; We can judge by observing the surface and flatness of the square tube. If the surface of the square tube is relatively flat, it can reflect that the square tube is good, otherwise, if
Dimensional stability for high-precision square tubes, the required accuracy is high, so the dimensional stability must be maintained. Due to straightening in the air and slow cooling speed, it has the effect of stabilization and will increase the number of residual square tubes in the, so it must be cooled; Reduce quenching deformation because the square tube is slender, it is easy to deform during quenching so its deformation must be strictly controlled. Heat treatment is a key process. In the process of quenching and cooling, the cold plasticity shall be corrected in time, which is a key step to ensure the improvement of its qualification rate. Therefore, hot bath quenching or cooling in oil for a fixed time shall be carried out to propose thermal correction.
.In the case of dynamic load, plastic design usually calculates the allowable stress 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, it can be calculated by the formula a = W. replacing the calculated strength with plasticity can improve the bearing capacity of the member by 14%.
The calculation method theory of square tube mechanics is feasible to calculate static structures, such as warehouses, houses and bridges, 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%.
The 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.
The first is the influence of external conditions. It mainly depends on the medium characteristics and temperature around the square pipe and whether the medium around the pipe is corrosive. Because the corrosivity of the medium is closely related to the microorganisms contained in the soil. And if it is a long-distance pipeline, the soil environmental properties are more complex. In addition, the temperature of the environment where the pipeline is located will also affect the corrosion of the square pipe. If the temperature is high, the corrosion speed will also be accelerated, while if the temperature is low, the corrosion speed will be slowed down.
B. tool steel: (a) carbon tool steel; (b) Alloy tool steel; (c) High speed tool steel.
0 200× 200×0～ 0 220× 220×0～ 0 250× 250×0～ 0 280× 280×0～ 0 300× 300×0～ 0 320× 320×0～ 0 350× 350×0～ 0 380× 380×0～ 0 400× 400×0～ 0 420× 420×0～ 0 450× 450×0～ 0 480× 480×0～ 0 500× 500×Standard treatment of steps for preventing oxidation of 0 ~ 0 square tube square tube is a kind of metallic maintenance. The main components are iron and zinc. It is easy to have redox reaction in the air. Once the reaction occurs, many new substances have taken place, in order to maintain the original relevant characteristics, anti-oxidation treatment is required. The direct reason is to prevent the square tube from reacting with the oxygen in the air, which is the way to isolate the oxygen in the air. Today, this article makes a relatively standardized treatment on the relevant steps to prevent oxidation of square tubes: the key depends on what kind of antirust paint you use. 1. If you use epoxy zinc rich or iron rich antirust paint, you can directly spray fluorocarbon paint on it; 2 if alkyd antirust or red lead is used, it shall be cleaned with paint remover and sprayed with epoxy zinc rich or iron rich antirust paint again before fluorocarbon paint can be sprayed.
quality.When processing the square tube, some processes need to heat the seamless square tube. The heating operation in the processing of the seamless square tube plays a very key role in the quality of the finished seamless square tube.
According to the welding specification, process test and process analysis, it is determined that the butt weld of Q345B square pipe adopts double-layer CO2 gas shielded welding. H08Mn2SiA, 2mm welding wire for welding material; The shielding gas is pure CO2 gas. The welding current of layer weld is 200 ~ 250A, and that of the second layer is 240 ~ 320A; The arc voltage is 24 ~ 26V. The process requirement is that the layer weld must be fully welded to ensure good back forming; The welding current, arc voltage, wire feeding speed and welding speed can be adjusted according to the equipment model.
Now in many construction projects, we can see the shadow of q355b square tube, and the performance and quality of deformation, stamping, cutting and other processing are based on hardness, which is also the guarantee of mechanical properties. Based on the above, it is very important to test the hardness of q355b square tube.
Drawing process flow of square tube in the production process of square tube, it needs a lot of processes to complete the production process, that is, when the hot working stop forging temperature is in the phase zone (between, and 40), ferrite precipitates in bands from austenite along the metal flow direction, and the undigested austenite is cut into bands. When it is cooled to a, the banded austenite is transformed into banded pearlite. This can be improved or eliminated by increasing the final rolling temperature, increasing the forging ratio, diffusion annealing and normalizing.
Due to the increase of square tube production, there are more and more fake and shoddy square tubes in the market. How to distinguish the fake and shoddy square tubes? Let me teach you some points to distinguish the fake and shoddy square tubes.
You can really feel that the square tube is widely used in the development, and q355b square tube factory continues to extend in the technical level, which makes the current square tube develop more widely.
Ibb.After aluminum deoxidation in molten steel, & omega; When (ALS) is 0.015% ~ 0.025%, calcium treatment can achieve better effect on the denaturation of Al203.
During the storage of square tubes, pay attention to the stacking layers of square tubes to avoid local stress at the tube end caused by too many layers, resulting in radial plastic deformation and layer damage of square tubes. It is recommended that the stacking layers of smooth pipes refer to apirp 5l1-2009 Recommended Practice for railway transportation of square pipes for pipelines or apirp 5lw-2009 Recommended Practice for ship and sea vessel transportation of square pipes for pipelines. It can also be determined by test or implemented according to the safe stacking height of square pipes. The stacking layers of pipes shall be implemented according to GBT 23257-2009 polyethylene layer of buried steel pipelines.
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.