1.Cleanliness requirement: weight of impurities ≤100mg/m2（inner wall），allowed max size of impurity：200um，（not more than three 315umX315umX600um impurities for each assembly）；fiber impurity 1200 um（not more than ten 90umX90umX2000um soft fiber impurities for each assembly）. Unallowed impurity：such as quartz sand, emery, glass.

2.Pulling-out force: For high pressure pipe assembly, pulling-out force should be more than 600N; For oil return pipe, under criming method, pulling-out force ＞ 500N；Under clamp connection method, pulling-out force ＞ 200N.

3.Burst pressure: high pressure pipe assembly ＞49Mpa，oil return pipe assembly ＞7Mpa.

4.Welding strength of high pressure pipe: welding strength ≥ 290N/mm2 at 23℃±5℃.

5.Volume variation performs well, the better to lower the noise.

6.Fixed with noise reducing tube in assembly to lower the noise.

7.Position displacement between bracket and bushing to tube ＞ 50N.

8.High-pressure pipe assembly can meet 225000 times high-temperature impulse test.

High-low pressure pipe assembly is consist of high-pressure pipe assembly and oil return pipe assembly. High-pressure assembly is connected with oil return pipe assembly by washer, then fixed by metal bracket. we supply the goods by assembly. reducing the assembly processing time and increase productivity.