Chemical composition (nominal) %

Forms of supply

Hollow bar-Finishes, dimensions and tolerances
Hollow bar Sanmac 4435 is stocked in a large number of sizes up to 250 mm outside diameter in the solution-annealed and white-pickled condition. See catalogue S-110-ENG, S-029-ENG or S-02909-ENG.

Dimensions are given as outside and inside diameter with guaranteed component sizes after machining for OD<2.5 x OD.

Outside diameter +2 / -0 %, but minimum +1 / -0 mm
Inside diameter +0 / -2 %, but minimum +0 / -1 mm
Straightness +/-1.5mm/m
Better tolerances can be supplied to special order.

Other forms of supply
Bar
Steel with improved machinability, Sanmac, is also available in round bar and billet.

Filler metals for welding
The sizes listed below are Sandvik stock standard. The local stocks carry sizes in common demand on the market. For technical information on the filler metals please refer to brochures S-2361-ENG and S-2362-ENG.

Wire electrodes and filler wire/rods:
Sandvik 19.12.3.L: 0.80, 1.00, 1,20, 1.60, 2.00, 2.40, 3.00, 3.20, 4.00 mm

Covered electrodes
Sandvik 19.12.3.LR: 1.6, 2.0, 2.5, 3.25, 4.0 mm
Sandvik 19.12.3.LB: 2.0, 2.5, 3.25, 4.0, 5.0 mm
Sandvik 19.12.3.LRHD: 2.5, 3.25, 4.0, 5.0 mm

Mechanical properties

For hollow bar with wall thickness greater than 10 mm (0.4 in.) the proof strength may fall short of the stated values by approximately 10 MPa (1.4 ksi).

At 20°C (68°F)

1 MPa = 1 N/mm²
a) R_p0.2  and R_p1.0 correspond to 0.2% offset and 1.0% offset yield strength, respectively.
b) Based on L₀ = 5.65 ÖS₀ where L₀ is the original gauge length and S₀  the original cross-section area.

Impact strength

Due to its austenitic micro structure, Sandvik Sanmac 4435 has very good impact strength both at room temperature and at cryogenic temperatures.

Tests have demonstrated that the steel fulfils the requirements according to the European standards EN 13445-2 (UFPV-2) ( (min. 60 J (44 ft-lb) at -270 ^oC (-455 ^oF) and EN 10216-5 (min. 60 J (44 ft-lb) at -196 ^oC (-320 ^oF).

Physical properties

Density: 8.0 g/cm³, 0.29 lb/in³

Corrosion resistance

General corrosion

Sandvik Sanmac 4435 has good resistance to:

• Organic acids at high concentrations and temperatures, with the exception of formic acid and acids with corrosive contaminants
• Inorganic acids, e.g. phosphoric acid, at moderate concentrations and temperatures, and sulphuric acid below 20% at moderate temperatures. The steel can also be used in sulphuric acid of concentrations above 90% at low temperature.
• E.g. sulphates, sulphides and sulphites
• Caustic environments

Intergranular corrosion

Sandvik Sanmac 4435 has a low carbon content and therefore better resistance to intergranular corrosion than other steels of type AISI 316.

Pitting and crevice corrosion

Resistance to these types of corrosion improves with molybdenum content. Sandvik 4435, containing approximately 2.6% molybdenum, has substantially higher resistance to attack than steels of type AISI 304 and also better resistance than ordinary AISI 316/316L steels with 2.1% molybdenum.

Stress corrosion cracking

Austenitic steels are susceptible to stress corrosion cracking. This may occur at temperatures above about 60°C (140°F) if the steel is subjected to tensile stresses and at the same time comes into contact with certain solutions, particularly those containing chlorides. In applications demanding high resistance to stress corrosion cracking, the austenitic-ferritic steels Sandvik SAF 2304, Sandvik 10RE51 or Sandvik Sanmac SAF 2205 have higher resistance to stress corrosion cracking than 4435.

Gas corrosion

Sandvik Sanmac 4435 can be used in:

• Air up to 850°C (1560°)
• Steam up to 750°C (1380°F)

Creep behaviour should also be taken into account when using the steel in the creep range .In flue gases containing sulphur, the corrosion resistance is reduced. In such environments Sanmac 4435 can be used at temperatures up to 600-750°C (1110-1380°F) depending on service conditions.

Factors to consider are whether the atmosphere is oxidising or reducing, i.e. the oxygen content, and whether impurities such as sodium and vanadium are present.

Heat treatment

Hollow bar is delivered in heat treated condition.

If further heat treatment is needed after further processing the following is recommended:

Stress relieving
850-950°C (1560-1740°F)

Solution annealing
1000-1100°C (1830-2010°F), rapid cooling in air or water.

Welding

Suitable welding methods for Sandvik Sanmac 4435 are manual metal-arc welding (MMA) with covered electrodes and gas-shielded arc welding with the TIG and MIG methods as first choice. Pre-heating and post-weld heat treatment is normally not necessary.
Due to the fact that this material is alloyed in such a way that it shall have good machinability there can be higher amounts of surface oxides on the weld beads compared to standard 316L steels. This may lead to arc instability during TIG welding, especially at autogenous welding. A correct setting of the welding current is of great importance. However, when filler metal is used, the weldability is the same as for standard 316L steels.
Since the material has low thermal conductivity and high thermal expansion, welding must be carried out with a low heat input and with welding plans well thought out in advance so that the deformation of the welded joint can be kept under control. If, despite these precautions, it is foreseen that the residual stresses might impair the function of the weldment, we recommend stress relieving of the entire structure. See recommendations under "Heat treatment".
Recommendations of filler metal:

Applications

Sanamc 4435 is used in a wide range of industrial applications where steels of type ASTM 304/304L have insufficient corrosion resistance. Typical applications are :

• Machines parts for tube and pipe fittings
• Components for valves, pumps, heat exchangers and vessels
• Different tubular shafts in chemical, petrochemical, fertiliser, pulp and paper and power industries as well as in the production of pharmaceuticals, foods and beverages