When excavating a tunnel in a stratum where the rock is not hard and complete， it is generally necessary to excavate a diversion pit (also known as pilot hole) and set temporary support.
6Longitudinal welded pipe has the advantages of simple production and processing technology， high production efficiency， low cost and rapid development trend. The compressive strength of spiral welded pipe is generally higher than that of straight welded pipe. Narrow blank can be used to produce welded pipe with large pipe diameter and blank with the same total width can also be used to produce welded pipe with different pipe diameter. However， the welding length is increased by ~ compared with the straight seam pipe with the same length， and the production rate is low.
cOrlandoThe side length of I-beam is small and the height is large so it can only bear the force in one direction.
Thanks to a zinc tube，Products Show stand in the formation and development of painful microorganisms.
UAgstafa Spray is OK. This method can not only completely remove rust，Lincoln15CrMoG large diameter alloy pipeSpecial application environment oxide and dirt， but also the welded pipe will be affected by abrasive impact and friction， resulting in the average roughness of the welded pipe.
Zt Polished stainless steel pipes shall be subject to internal inspection and strict manual selection by the steel pipe quality inspector through metal detector (or hydrostatic test)， and qualified products shall be packaged and delivered.
The reinforced concrete surface reinforcement method has the advantages of simple construction technology and strong adaptability， which can greatly improve the bearing capacity， flexural stiffness and ductility of the brick wall. At the same time， its natural frequency can be changed to improve its performance in normal use. It is mainly applicable to the solid wall， porous hollow brick wall and mm thick empty bucket brick wall with no cracks and shear in the original wall.
In the production process， the stainless glittering pipe is affected by the outside and product surface. Due to galvanizing，Products Show the corrosion protection is not corroded. This is the thickness of zinc， and the quality and strength of its coating depend on longevity.
hI-beam is mainly divided into ordinary I-beam， it is divided into wide， medium and narrow flange I-beams. The specifications of the first two are -， that is， the corresponding height is -. At the same height， the light I-beam has narrow flange， thin web and light weight. Wide flange I-beam， also known as H-beam， is characterized by two parallel legs and no inclination on the inner side of the legs. It belongs to economic section steel and is rolled on four high universal mill，Products Show so it is also called "universal I-beam". Ordinary I-beam and light I-beam have formed national standards.
IThe first is people. Human factors are the control focus of welding. Therefore， before welding，Lincoln15CrMoG large diameter alloy pipeSpecial application environment welders with skilled technology and welder certificate shall be selected for necessary technical training and disclosure. It shall not be replaced at will to ensure the relative stability of the welders welding the pipeline.
TQuality department As long as the pipe material is high-strength alloy steel， including alloy steel pipes with temperature resistance， pressure resistance， wear resistance and low temperature resistance， the welding process shall be focused on preventing the tendency of martensite structure and cracks due to welding high-temperature operation. The general process requirements are that the welding rod shall be selected and baked as required and sent to the welder for use. The oil and water shall be removed before welding on both sides of the weld Rust and sundries shall be removed and cleaned. The welding line energy shall be as small as possible to minimize the swing during the welding process. The arrangement of the last weld shall have annealing effect on the heat affected zone as far as possible. Slow cooling after welding， cover with asbestos cloth， etc.
gM East West derusting: if the galvanized pipe surface is rusty， the manufacturer will choose East West derusting and polish it with a steel wire brush
Galvanized pipe has excellent corrosion resistance
External steel bonding reinforcement method is a more traditional reinforcement method. The utility model uses an adhesive to paste the steel plate or reinforcement mesh on the cracked part of the wall to achieve the purpose of reinforcement. The commonly used adhesive is usually epoxy resin. This method is simple and fast in construction and has little impact on production and life. Basically，Reinforcement, galvanized pipe, seamless pipe, welded pipe, alloy pipe, I-beam-Shandong Kaiwen metal material Co., Ltd the bearing capacity of the wall can be greatly improved without changing the shape and internal use space of the components. It is mainly applicable to the reinforcement of walls that do not allow to increase the section size of original components， but can greatly increase the section bearing capacity.
Quality documentsr Sulfur is a harmful impurity in steel. Steel with high sulfur content is easy to embrittle during pressure processing at high temperature，
According to the pipe wall thickness， pipes made of relatively thin materials such as steel strip can be welded with high frequency， and some thin-walled pipes can be welded with shielding gas; Pipes with wall thickness more than mm can be welded by hand.
bOrlandoBlanking shall be carried out according to the design and site， and then the groove shall be made with a grinder with a groove angle of ° ~ °. Fix the processed pipe on the support， and the gap between the two pipes is mm ~ mm， and then weld.
xVThe advantage of the reinforcement mesh system is ecological. It is filled with natural stone materials. There is a gap between the stone materials to allow plants to grow in it. It can also plant plants on it. It has the dual effects of engineering slope protection and plant slope protection. The Ecological Grid mat is a combination with a height of cm ~ cm， mostly a multi grid box separated by spacer mesh.
There shall be no bending at the welded junction， and there shall be no staggered joint during assembly. Electric welding positioning is generally spot welding. After inspection and straightening， the free conversion method shall be used for welding as far as possible.