Clamshell connection
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If the pipe is made of 304 material, what material should be used for the GB3764 ferrule? Based on the principles of ferrule sealing, it seems that the material of the ferrule should be harder than that of the pipe, but the standards do not specify this exactly. I would appreciate it if experts could provide some guidance!
Stainless steel pipes should be equipped with stainless steel collars
Stainless steel ferrule rigid pipe fittings cost between a dozen yuan and over a hundred yuan, depending on the choice you make
Referencing the technical specifications for bayonet pipe fittings in standard GB-T 3765-2008, Article 4.3 specifies that stainless steel bayonets are to be used in combination with stainless steel fitting bodies and stainless steel pipes.
I mean, as a standard, stainless steel pipes are paired with stainless steel ferrules, but for example, if the pipe is made of 304 material, should the ferrule also be 304, or should it be a harder martensitic stainless steel such as 20Cr13?
Personally, I think 304 pipes should be paired with 304 compression fittings; better ones can also be used
The bushing shall be an annealed stainless steel tube with a hardness of less than or equal to HB95. The raw material for single sleeve production should be ordinary pipe material, with a hardness generally below HRC22. After processing and shaping, hardening is carried out; the hardness achieved as a result should generally be around 800 on a Vickers hardness scale. Some manufacturers also use stainless steel pipes with a hardness of HRC25-28 to directly fabricate single ferrules, but this approach carries significant risks; under high pressure, the ferrules can come off completely.
Single card sleeve or double card sleeve? Theoretically, it is sufficient for the hardness of the ferrule connector to be higher than that of the pipe. Here are several standards for ferrule-style pipe fittings for your reference:
ASTM A269: General-purpose seamless and welded austenitic stainless steel tubes [Note: Inner diameter of 1/4\" (6.35 mm) or more, wall thickness of 0.02\" (0.51 mm) or more] ASTM A213: Seamless ferritic and austenitic alloy steel tubes for boilers, superheaters, and heat exchangers ASTM A312: Seamless, welded, and deeply drawn austenitic stainless steel pipes [Note: Specifies materials, heat treatment, dimensions (refer to ASME B36.19M including pressure rating calculations)]