Description
**4L gate valve
Gate valve
Design standard:API**0/ISO****4/API**3
Size:1/2''~*2
Pressure range:**0LB~***0LB
Valve material instruction
Other corrosion resistance/high temperature resist
**4L,Alloy *0,AISI **1,AISI **0S.
Grade **4L stainless steel is a non-stabilized austenitic stainless
steel with low carbon content. This high alloy stainless steel is
added with copper to improve its resistance to strong reducing
acids, such as sulphuric acid. The steel is also resistant to
stress corrosion cracking and crevice corrosion. Grade **4L is
non-magnetic, and offers excellent formability, toughness and
weldability.
Chemical Formula
Fe, <0.*2% C, ****3% Cr, ****8% Ni, **5% Mo, <2.0% Mn,
<1.0% Si, <0.**5% P, <0.**5% S, 1.**2.0% Cu
Corrosion Resistance
Grade **4L stainless steels have excellent resistance to warm
seawater and chloride attack. The high resistance of grade **4L
against stress corrosion cracking is due to the presence of high
amounts of nickel in its composition. Moreover, the addition of
copper to these grades develops resistance to sulphuric acid and
other reducing agents in both aggressive and mild conditions.
The corrosion resistance of grade **4L is intermediate between
super austenitic grades, with 6% molybdenum content, and standard
**6L austenitic grades. Grade **4L is less resistant to nitric acid
than grades **4L and **0L, which are free of molybdenum. This steel
grade needs to be solution treated following cold working, to
achieve maximum stress corrosion cracking resistance under critical
environments.
Heat Resistance
Grade **4L stainless steels offer good oxidation resistance.
However, the structural stability of this grade collapses at high
temperatures, particularly above **0°C.
Heat Treatment
Grade **4L stainless steels can be solution heat-treated at ***0 to
***5°C, following by rapid cooling. Thermal treatment is suitable
for hardening these grades.
Welding
Welding of grade **4L stainless steels can be performed using all
conventional methods. This grade does not require pre-heat and
post-weld heat treatments. Grade **4L can be subjected to hot
cracking in constrained weldment. Grade **4L electrodes and rods
are used for welding grade **4L steels according to AS ***4.6.
Fabrication
Grade **4L stainless steels are high purity steels with low sulphur
content. They can be machined using any standard methods. These
grades can be readily bent to a small radius under cold conditions.
Although subsequent annealing is not required in most cases, it
should be carried out when the fabrication is performed under
severe stress corrosion cracking conditions.
