Hardness test is to determine the hardness of seamless qb square pipe by slowly pressing a hard indenter on the sample surface according to the specified conditions， and then testing the indentation depth or size.
8Brinell hardness， Rockwell hardness and Vickers hardness are commonly used.
wSteel pipe for geological drilling (yb-) is a steel pipe used by geological departments for core drilling. It can be divided into drill pipe， drill collar， core pipe， casing，Q345D square tube sedimentation pipe，150 hot dip galvanized pipeRelief of financial pressure etc.
Yield point of square tube (& sigma; s): the stress of metal material with yield phenomenon when the sample can continue to elongate without increasing (maintaining constant) the force during the tensile process， which is called the yield point. If the stress decreases， the upper and lower yield points shall be distinguished. The unit of yield point is nmm (MPA).
IPresovPreheating must be carried out before heat treatment of qb square tube so as to better ensure that there will be no many problems in the whole heat treatment process of qb square tube， and the quality of qb square tube will also be well guaranteed.
OqThe square tube shall be painted correctly. The square tube， rectangular tube， seamless square tube and galvanized square tube shall be sold professionally. The performance of galvanized tube is stable， safe， reliable and maintenance free. The technical level has reached the domestic level and the advanced level of similar international products. Otherwise， the square tube will be corroded. The correct paint shall also be selected during painting，Q345D square tube In this way， we can ensure that the square tube can be used more firmly， so as to ensure that the square tube will be better and better in future use. The square tube is used a lot in the soul. Each kind of square tube has a different role for the other tube. We choose different square tubes in the correct way， which can increase the performance of the square tube and be applied to different fields. Let me briefly introduce the square tube below.
General shot blasting is used for square tube with regular shape. Several polishing heads are up， down， with high efficiency and little pollution.
Requirements for samples samples can be taken from metal pipes with qualified appearance. Generally sawing is adopted.
aHot dip galvanized square pipe is widely used， mainly in curtain wall， solar power generation support， construction， machinery and steel structure engineering，Q345D square tube machinery and construction. The effect of cold galvanized square tube is far from that of hot galvanized square tube; How to distinguish hot galvanized square pipe from cold galvanized square pipe?
DThe analytical technology of square tube sizing rolling. When sizing rolling is adopted， because there is no tool on the inner surface，150 hot dip galvanized pipeRelief of financial pressure the inner surface of the rolled material is angular. The occurrence mechanism of this phenomenon and the countermeasures to be taken are clarified by using the three-dimensional finite element method.
DManufacturing costHigh productivity of square tube: the efficiency of cold production of mechanical parts is very high， especially for parts with large batch. Cold production can be several times， several times or even hundreds of times higher than cutting. For example， the use of cold pin for automobile is twice higher than that of cutting. At present， cold pin automata is used to improve productivity. The productivity of table cooling automata is equivalent to that of ordinary lathes or shaft self-propelled machines.
eKNow， with the continuous development of qb square tube its use is becoming more and more extensive， and the technology is also following up. Therefore we still look forward to the development of qb square tube in the future.
With the development of economy， there are a lot of demands for project construction，Galvanized pipe_ Galvanized square pipe_ Seamless steel pipe_ Square tube - Wuxi Jiahang which leads to the continuous increase of square pipe. The of square pipe is more complex. Great efforts should be made in the selection of raw materials， structured treatment and so on.
In the process of square pipe， we will conduct a variety of tests on it to ensure that the square pipe can be better used in practice. In order to make better use of large-diameter steel pipe， we will continue to innovate. Lets introduce the main elements contained in the lower pipe. For the martensitic chromium square tube， the main elements affecting the are chromium， carbon and molybdenum; For Martensitic chromium nickel square tube， the main influencing elements are nickel， molybdenum， aluminum， cobalt， Fangguan has a brand-new development
DPurpose of square tube the purpose of square tube includes construction， machinery， steel construction and other projects， shipbuilding， solar power generation support， steel structure engineering， electric products ( pieces)
The square tube is a low alloy high strength steel
mBoth internal and external welding of square pipes are carried out by American Lincoln Electric welding machine for single wire or double wire submerged arc welding， so as to obtain stable welding specifications.
zRIn order to ensure excellent coating quality， the coating is required to be firmly attached to the surface of the coated object. This depends on the quality of the coating itself; On the other hand， it depends on the quality of the coated surface treatment before construction. After various surface treatments， the coating quality and economic effect are very different.
Material of square tube: q Q (Mn)， #， alloy steel， stainless steel.