As the stainless steel pipe fittings vary in size, according to the unique place of stainless steel pipe welding, as far as possible to reduce the amount of heat input, so the use of manual arc welding, argon arc welding two methods, d> Φ159 mm using argon arc welding, Arc welding cover. D ≦ Φ159 mm full use of argon arc welding. Stainless steel pipe welding technical requirements are as follows:
① manual arc welding when the use of direct reverse welding machine, argon arc welding with DC is followed;
② welding should be welded with stainless steel wire brush off the surface of the oxide scale, and acetone washing; electrode should be 200-250 ℃ drying 1h, with the take with;
③ Clean the oil in the range of 25 mm on both sides of the workpiece groove before welding, and wash the groove on both sides with acetone on both sides of the 25 mm range;
④ argon arc welding, the nozzle diameter Φ2 mm, tungsten is extremely pot tungsten, specifications Φ2.5 mm; ⑤ TIG welding stainless steel, the back must be filled with argon protection, in order to ensure the back forming. The flow rate is 5-14L / min and the flow rate of the front argon is 12 to 13L / min.
Bottom welding seam thickness should be as thin as possible, with the root fusion outstanding, when the arc into a slow slope, if the arc shrinkage, the application of grinding machine wear off. Must be in the groove within the arc arc, arc should be filled with craters, to prevent cracks in the arc.
As the stainless steel pipe fittings for the stainless steel pipe, in order to prevent the precipitation of carbide precipitation and intergranular corrosion, should strictly control the inter-layer temperature and after welding cooling rate, the requirements of the inter-layer temperature control below 60 ℃, welding water immediately after the water, While the use of sub-welding. This symmetrical dispersion of the welding sequence, you can increase the cooling rate of the connector, but also reduce the welding stress.
The design and optimization of stainless steel pipe fittings, the preparation technology of stainless steel pipe fittings, the theoretical design and experimental analysis of axial compression performance were studied. Whether the angle of the laying of stainless steel pipe or axial / ring to the cross-layer pipe fittings, the appropriate content of the annular layer can significantly improve the axial strength of pipe fittings. After the 20% angle laying (axial laying) was changed to the torus, the axial compressive strength of the stainless steel pipe with the winding angle of 20 ° was increased by about twice, and the axial compressive strength of the ortho-laid stainless steel pipe Increased by more than 10%.
The bearing capacity of X-33 and AtlasV carrier rock bolts is analyzed by finite element model. It is pointed out that the integrated bearing capacity of X-33 thrust support is better , Suitable for more complex load conditions, and AtlasV thrust bracket structure of the compression load capacity is better, suitable for large thrust-based load conditions.