The difference between hot-dip galvanized square pipe and cold-dip galvanized square pipe is mainly from the following aspects: the appearance of hot-dip galvanized square pipe is slightly rough compared with cold-dip galvanized square pipe; The appearance of cold galvanized square pipe is smooth and bright.
If the test results of square tubes fail to meet the provisions of product standards， the unqualified ones shall be selected， and double the number of samples shall be taken from the same batch of square tubes for re inspection of unqualified items. If the re inspection results (including any index required by the test of the project) are unqualified， the batch of square tubes shall not be delivered. If the following inspection items fail to pass the preliminary inspection， re inspection is not allowed: A. There are white spots in the low magnification; b. Microscopic.
LahoskFunctional index analysis of square tube - mechanical function of plastic square tube.
The characteristics of square pipe are as follows: the production process of square pipe is simple， the production efficiency is high， the cost is low and the development is fast. The strength of spiral square pipe is generally higher than that of straight seam square pipe. It can produce square pipe with larger pipe diameter with narrow blank， and square pipe with different pipe diameter with blank of the same width. However， compared with straight seam pipe of the same length， the weld length is increased by ~， which will be oriented to the whole country for a long time Individuals and enterprises provide all kinds of square tubes， square rectangular tubes， seamless square tubes， galvanized square tubes， galvanized tubes， on-site settlement， honest operation，LahoskHow much is a 60 galvanized pipe， local offices， long-term cooperation， and low production speed. Therefore， most of the smaller square tubes adopt straight seam welding， and most of the large-diameter square tubes adopt spiral welding.
Islamic Republic of IranShip carbon steel square pipe (gb-) is a carbon steel square pipe for ship class I pressure pipe system， class II pressure pipe system， boiler and superheater. It is a long-term business square pipe， square pipe， seamless square pipe， galvanized square pipe and galvanized pipe. Welcome to consult. The working temperature of carbon steel square pipe wall shall not exceed ℃， and the working temperature of alloy steel square pipe wall shall exceed ℃.
The strength， plasticity and hardness discussed above in fatigue QB are the indicators of the mechanical properties of metals under static load. In fact， many machine parts work under cyclic load under which fatigue will occur.
Comprehensive classification ordinary steel A. carbon structural steel: (a) Q (b) Q (b); (c) Q( C)； (d) Q( B)； (e) Q.
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 flattening speed of the sample can be ~ mmin.
Large diameter qb square tube production standard classification square tube is divided according to production standard: national standard square tube， Japanese standard square tube， British standard square tube， European standard square tube and non-standard square tube.
Total quality assuranceThe second is the pickling of the square pipe. Both chemical and electrolytic methods are used when pickling the square pipe. These two methods can remove the oxide skin of the square pipe.
There are many processing technologies for square tubes. I won"t introduce the specific processing technology here. We only know about the processing technology of each other"s tubes. We may have insufficient understanding of its heating technology. Next， I"ll give you a detailed introduction to the heating technology of the lower tubes.
Square tubes for low and medium pressure boilers (gb-) are high-quality carbon structural steel hot-rolled and cold drawn (rolled) square tubes for superheated steam tubes， boiling water tubes for low and medium pressure boilers of various structures and superheated steam tubes， small smoke tubes and arch brick tubes for locomotive boilers. Square tubes for high-pressure boilers (gb- is a high-quality carbon steel， alloy steel and stainless heat-resistant steel square tube for the heating surface of water tube boilers with high pressure and above. High pressure square tube for chemical fertilizer equipment (GB - is a high-quality carbon structural steel and alloy steel square tube suitable for chemical equipment and pipelines with working temperature of - ~ ℃ and working pressure of ~ mA.
During the pushing process of spot welding and repair welding elbows there will be thinning， the products produced must be unqualified. Generally， there are about wires thinned. If the technology is not good or the drawn pipe is used， the thickness is significantly lower than the standard.
Quality assuranceZinc layer thickness: there is a great difference between cold galvanized square pipe and hot galvanized square pipe in galvanizing process; Cold galvanized square pipes are prone to & ldquo; Electric burning & rdquo; The color of this part is gray and the zinc layer is thick. It is easy to form a current dead angle at the corner， resulting in an under current area. The zinc layer at this part is thin， but the overall zinc layer is thin， and the thickness of the outer wall zinc layer is μ m-μ m. The and outer walls of the hot-dip galvanized square tube are attached with zinc layer， and there will be water marks and a few zinc tumors， but the overall zinc layer is thick， and the thickness of the zinc layer on the inner and outer walls of the square tube is -mu; M above. The nature of QB square tube!
Now， Fangguan can achieve such good results in the market， which is completely inseparable from the manufacturers" hard work in technology. I believe that the Fangguan market will be better and better in the future.
QB square tube is a product appeared in recent years， which mainly has strict tolerance and roughness for the dimensions of inner hole and outer wall. Production process classification of large-diameter qb square tube large-diameter qb square tube is divided into hot-rolled seamless square tube， cold drawn seamless square tube， qb square tube is divided into: (a) by process & mdash& mdash; Arc welded square pipe， resistance welded square pipe (high frequency and low frequency)， gas welded square pipe and furnace welded square pipe (b) are divided by weld & mdash& mdash; Material classification of straight seam welded square pipe and spiral welded square pipe large diameter qb square pipe: plain carbon steel square pipe and low alloy square pipe. Ordinary carbon steel is divided into Q Q q SS， # steel， # steel， etc; Low alloy steels are divided into q Mn， Q， St-， etc.
LahoskStrength 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， wire rod， reinforcement， medium diameter steel pipe， but they must be covered and padded; Some small steel pipes， steel sheets，LahoskPP square tube， 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， 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， 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.， 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，LahoskHow much is galvanized 20 square tube， 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
Ship carbon steel square pipe (gb-) is a carbon steel square pipe for ship class I pressure pipe system， class II pressure pipe system， boiler and superheater. It is a long-term business square pipe， square pipe， seamless square pipe， galvanized square pipe and galvanized pipe. Welcome to consult. The working temperature of carbon steel square pipe wall shall not exceed ℃， and the working temperature of alloy steel square pipe wall shall exceed ℃.
Stage ( & mdash; )
