Stainless Steel - Grade 444
CS444 is a low carbon, dual stabilised, molybdenum containing ferritic stainless steel with good ductility, toughness and resistance to sensitisation, even in the welds. With 18% chromium and 2% molybdenum, the steel has good pitting resistance and crevice corrosion resistance, similar to CS316 and good general corrosion resistance and oxidation resistance, similar to 316 in most environments. Being a ferritic stainless steel, CS444 is not susceptible to Stress Corrosion Cracking. Annealed CS444 is ductile and can be formed using a wide range of roll forming or mild stretch bending operations as well as the more common drawing and bending operations. CS444 does not harden excessively during cold working.
The steel has limited weldability and should not be used in the as-welded condition for dynamic or impact loaded structures. As with most ferritic stainless steels, CS444 can undergo grain growth in the heat affected zone of weldments, which may adversely affect the mechanical properties in these zones. Applications involving welded CS444 are thus generally limited to a thickness of 2.5mm.
CS444 has good pitting resistance and is thus suitable for roofing and cladding in marine environments, as well as hot water tanks and geysers, heat exchanger tubing and food processing equipment.
Other tolerances may be available on request. Further information is available in the Product Guide, which can be obtained from the Technical Customer Services Department or can be found at www.columbus.co.za
In accordance with ASTM A240 (444) and EN 10088-2(1.4521).
1) Niobium substitution of titanium stabilisation (% by mass) = Ti (% by mass)
2)Niobium substitution of titanium stabilisation (% by mass) = 7/4Ti (% by mass)
In accordance with ASTM A240 (444) and EN 10088-2(1.4521)
0.2% Proof Stress (MPa)
Tensile Strength (MPa)
PROPERTIES AT ELEVATED TEMPERATURES
The properties quoted below are typical of annealed CS444. These values are given as a guideline only, and should not be used for design purposes
SHORT TIME ELEVATED TEMPERATURE TENSILE STRENGTH
Tensile Strength (MPa)
0.2% Proof Stress (MPA)
MAXIMUM RECOMMENDED SERVICE TEMPERATURE
(In oxidising conditions)
The values given below are for 20°C, unless otherwise specified.
Modulus of Elasticity in Tension
Modulus of Elasticity in Torsion
Specific Heat Capacity
Mean Co-effcient of Thermal Expansior
@100°C - 26.8W/mK
@500°C - 27.1W/mK
0-100°C - 10.8μm/mK
0-315°C - 11.6μm/mK
0-540°C - 12.0μm/mK
0-700°C - 12.5μm/mK
1 405-1 495°C
THERMAL PROCESSING & FABRICATION
Annealing is achieved by heating to between 760°C and 830°C for 90 minutes per 25mm followed by air quenching.
Stress relieving after welding is not normally required. Should this be necessary, temperatures between 200°C and 300°C are recommended.
Uniform heating of the steel in the range of 950°C to 1 050°C is required. The finishing temperature should be below 750°C. Extended holding times above 1 000°C should be avoided as excessive grain growth may occur and ductility may be detrimentally affected. All hot working operations should be followed by annealing and pickling and passivating to restore the mechanical properties and corrosion resistance.
CS444 has good formability characteristics with useful mechanical properties. Its good ductility allows it to be readily formed by bending and deep drawing. CS444 does not undergo significant work hardening when cold formed.
Being ferritic, CS444 is prone to grain growth in the heat affected zone of weldments. As such, the tensile, fatigue and toughness properties in the welded condition are relatively poor. CS444 should thus not be used for applications where tensile or dynamic loading will be experienced. CS444 is generally limited to a combined thickness of
3 mm in the welded condition, i.e. for lap joints, this is equivalent to
2 x 1,5 mm thickness being welded together. The use of austenitic filler metals such as types 308L, 309L or 316L will improve the ductility of welds to some extent but all welding procedures should nevertheless endeavour to maintain minimum heat inputs. The weld discolouration should be removed by pickling and passivating to restore maximum corrosion resistance.
CS444 has good resistance to a wide variety of corrosive environments. With 18% chromium and 2% molybdenum the steel has good pitting resistance, better than CS316, good crevice corrosion resistance, similar to CS316 and good general corrosion resistance and oxidation resistance, similar to CS316 in most environments. Atmospheric corrosion resistance is good and similar to CS316. Being a ferritic stainless steel, CS444 is not susceptible to stress corrosion cracking.
- Stainless Grades
- 3CR12 - Corrosion Resisting Steel
- Stainless Steel Grade 430
- Stainless Steel Grade 444
- Stainless Steel Grade 304
- Stainless Steel Grade 321
- Stainless Steel Grade 316
- Stainless Steel Grade 309
- Stainless Steel Grade 310
- Stainless Steel Grade 2001
- Stainless Steel Grade 2304
- Stainless Steel Grade 2205
- Stainless Steel Cromanite
- Material Selection
- Stainless Fabrication
- Stainless Surface Finishes
- Cleaning Stainless Steel