SUS329J4LDuplex Stainless Steel Bolt
Cold Forged FA Hex Bolts
The material is stainless steel wire made by Nippon Steel Stainless Corporation. Since SUS329J4L was not standardized in JIS G 4308 'Stainless steel wire', the steel grade name of the steel inspection certificate (mill sheet) is 'S329J4L'.
■What is Duplex Stainless Steel?
Stainless steel in which a ferrite structure and an austenite structure coexist.
It is also resistant to corrosion, crevice corrosion, and stress corrosion cracking in a chloride environment, and is significantly superior to SUS316. Since it is stronger than SUS304 and SUS316, it can be designed to be lighter.
■Chemical composition (typical example) and pitting corrosion resistance index (PREN) (reference value)
Although SUS304 or SUS316, which is an austenitic stainless steel, has superior performance to carbon steel in the general air environment, it comes into contact with seawater in which chlorine ions are present, and chlorine ions (Cl- In an environment where) is concentrated, the performance may not be sufficient in terms of durability. Specifically, there have been reports of stress corrosion cracking in stainless steel hexagon bolts used in heated pool sheds (environments where Cl-exists). SUS329J4L steel FA80 hexagon bolts have much better stress corrosion cracking resistance than SUS304 and SUS316 steel hexagon bolts.
■Corrosion comparison test (reference)
Figure 1
Figure 2
[1] Put 12% sodium hypochlorite solution in the water tank (amount is optional) [2] Warm with a heater from the outside of the water tank to promote corrosion (35 °C setting)
[3] SUS304 plate and SUS329J4L plate ( Stack two M10 drill holes + grooved),
tighten with a bolt + nut combination specified torque, install in the water tank so that it does not touch the solution, and cover it (Fig. 1)
[4] Saturated saline solution (500 ml ) at the start of the company ), Soak each sample in the same timing, warm it to about 80°C, and return it to the water tank after 8 hours (Fig. 2).
[5] When returning the sample, put 12% of sodium hypochlorite solution in the water tank (Any amount)
โบลท์หัวหกเหลี่ยมสแตนเลส / STAINLESS STEEL HEX HEAD BOLT 
