St TrudenLarge diameter rectangular square tubeMelting method of

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， alkali it is not allowed to stack with acid， 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， wire rod， reinforcement， medium diameter steel pipe， steel wire and steel wire rope can be stored in a well ventilated shed， but they must be covered and padded; Some small steel pipes， 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， enclosure， 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 m for manual operation， m for mechanical operation， and m for stacking width; A fixed channel shall be reserved between stacks， generally .m， and the access channel is generally ~ 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 .M; If it is muddy ground， it must be padded . ~ .m high. If it is an open site， the cement ground shall be padded with O & middot; ～O· m， . ~ . m higher than the sand and mud surface， the angle steel and channel steel shall be stacked in the open air， i.e. the mouth shall face down， 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， 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， the internal and external surfaces need to be coated with anti rust oil before storage; Steel pipes with serious corrosion shall not be kept for a long time after rust removal and shall be used as soon as possible. With the development of economy， all kinds of square tubes， rectangular 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. On the contrary， if the surface is not good

The surface of fake and inferior square tubes is easy to produce scabs. There are two reasons: the material of fake and inferior square tubes is uneven and there are many impurities. The guide equipment of fake and shoddy material manufacturers is simple and easy to stick to steel. These impurities are easy to scar after biting the roll.

St TrudenWhether the bottom is galvanized or painted; For paint， it is recommended to match: epoxy zinc rich um + epoxy micaceous iron intermediate paint um + polyurethane finish paint um. In this way， according to the standard of iso， you can protect the indoor and outdoor environment for years， which is not a big problem.

Purpose of square tube the purpose of square tube includes construction， machinery， steel construction and other projects， shipbuilding，St Truden76 galvanized square pipe， solar power generation support， steel structure engineering， electric products ( pieces)

MazabukaSquare pipe is the name of square pipe， that is steel pipe with equal side length. It is made of rolled strip steel after process treatment.

Stage ( & mdash; )

Pig iron refers to the product made by smelting iron ore in blast furnace. It is mainly used for steelmaking and square casting. Put the cast pig iron in the melting furnace to obtain cast iron (liquid)， and cast the liquid cast iron into a cast square pipe. This kind of cast iron is called cast iron.

The surface of fake and inferior square tubes is easy to produce scabs. There are two reasons: the material of fake and inferior square tubes is uneven and there are many impurities. The guide equipment of fake and shoddy material manufacturers is simple and easy to stick to steel. These impurities are easy to scar after biting the roll.

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 %.

For gas transmission: gas steam and liquefied petroleum gas.

assetsStage ( & mdash; )

Tool derusting mainly uses tools such as steel wire brush to polish the surface of square pipe， which can remove loose or oxidized scale， rust， welding slag， etc. The derusting of manual tools can reach grade SA and that of power tools can reach grade SA. If the square pipe surface is firmly attached with iron oxide scale， the derusting effect of tools is not ideal and can not reach the anchor depth required by construction.

When the vehicle is replaced with seamless square tube blank， so as to ensure the quality of parts and avoid wrinkles.

It is the process of drawing the die hole of the rolled metal blank (shape，St TrudenNational standard galvanized square pipe， pipe， product， etc.) into a section to reduce the length and increase. It is mostly used for cold processing.

quality special shaped square pipe is the general name of square pipes with other cross-section shapes except circular pipe. According to the different cross-section shape and size of steel pipe， it can be divided into special-shaped square pipe with equal wall thickness (code D)， special-shaped square pipe with unequal wall thickness (code BD) and special-shaped seamless steel pipe with variable diameter (code D) These special-shaped large-diameter qb square tubes are widely used in various structural parts， tools and mechanical parts. Compared with circular tubes， special-shaped tubes generally have large moment of inertia and section modulus， and have large bending and torsion resistance， which can greatly reduce the structural weight and save steel. Square tubes are an indispensable part of construction work

The qb square tube rolled from the strip steel through process treatment is generally to unpack， flatten， curl and weld the strip steel to form a round tube， then roll the round tube into a square tube， and then cut it to the required length. Nowadays， the forming of qb square tube has solid bending and empty bending. The bending degree of qb square tube shall not be greater than mm per meter， and the total bending degree shall not be greater than the actual bending of the total length. As the name suggests， the bending is compacted，St Truden65 galvanized square pipe， and the internal and external rollers and the internal and external walls of the tube blank are compacted in both directions during the actual bending.

According to metallographic classification， the annealed state of square tube: A. hypoeutectoid steel (ferrite + pearlite); b. Eutectoid steel (pearlite); c. Steel precipitation through a common square tube (pearlite + cementite); d. Ledeburite steel (pearlite + cementite).

St TrudenOil drilling pipe (yb-) is a square pipe used for internal or external thickening at both ends of oil drilling. Steel pipes are divided into turning wire and non turning wire. Turning wire pipe is connected with joint， and non turning wire pipe is connected with tool joint by butt welding.

The strength， plasticity and angle discussed later are the machine function indicators of metal under static load. In practice， many mechanical machines are under repeated load， and the whole opportunity is tired in this environment.

Square tube has a wide range of application fields. Its main field is the construction industry， which promotes the development of economic construction. Because the production process of square tube hole is different， the production design of square tube hole is also different. Next， I will introduce in detail the types of tube hole design below.