ASTM A213 316Ti Stainless Steel Seamless Round Pipe UNS S31635
Type 316Ti (UNS S31635) is a titanium stabilized version of Type
316 molybdenum-bearing austenitic stainless steel.
316Ti (UNS S31635) is a titanium stabilised version of 316
molybdenum-bearing austenitic stainless steel. The 316 alloys are
more resistant to general corrosion and pitting/crevice corrosion
than the conventional chromium-nickel austenitic stainless steels
such as 304. They also offer higher creep, stress-rupture and
tensile strength at elevated temperature. High carbon Alloy 316
stainless steel can be susceptible to sensitisation, the formation
of grain boundary chromium carbides at temperatures between
approximately 900 and 1500°F (425 to 815°C) which can result in
intergranular corrosion. Resistance to sensitisation is achieved in
Alloy 316Ti with titanium additions to stabilise the structure
against chromium carbide precipitation, which is the source of
sensitisation. This stabilisation is achieved by an intermediate
temperature heat treatment, during which the titanium reacts with
carbon to form titanium carbides. This significantly reduces
susceptibility to sensitisation in service by limiting the
formation of chromium carbides. Thus, the alloy can be used for
extended periods at elevated temperatures without compromising its
corrosion resistance. 316Ti has equvilent corrosion resistance to
sensitisation as the low carbon version 316L.
ASTM A213 316Ti Stainless Steel Seamless Pipe, UNS S31635 1.4571
The possibilities for cold forming 316Ti are very good. The
considerably greater strain hardening compared to plain steel
grades demands correspondingly higher forming forces. The annealing
colours or scaling occurring during hot forming or welding impair
the corrosion resistance. They must be removed by pickling,
grinding or sand-blasting (iron free). Metal-cutting machining must
be performed with tools made of high-quality high-speed steel (good
cooling necessary), or preferably with carbide tools, owing to the
strain hardening and the low thermal conductivity. The 316Ti
material version displays better cutting properties owing to the
specific addition of sulphur.
Good weldability using all process (except gas welding).
Notes on use
Owing to the addition of titanium as a carbode former, 316Ti is
resistant to intercrystalline corrosion, regardless of thickness
and cross-section and even when welded, in continuous operation at
up to 400 o C. Owing to the molybdenum content, 316Ti displays good
resistance to media containing chloride and to non-oxidising acids.
316Ti is used in the construction of apparatus for the chemical and
pharmaceutical industries, and for textile finishing.