Aeroval V155

Material Description

V155 is a martensitic Stainless Steel which could be strengthened by precipitation treatment leading a Cu-containing phase to precipitate in the alloy.  It is typically used for parts requiring corrosion resistance and high mechanical properties up to 315°C.  The proper chemical composition and the manufacturing process promote improved toughness in the transversal section and good ductililty; these features are obtained by balanced chemistry capable to limit the content of ferrite and by consumable electrode remelting practice capable to control the inclusion content accurately.

Applications

Aircraft components (structural parts, flap tracks and engine pylons), fabricated parts in high pressure corrosive environments including valves, shafts, fasteners, fittings and gears.

Corrosion and Oxidation Resistance

V155 exhibits good resistance to oxidation up to 600°C.  Long term exposure to elevated temperatures can result in reduced toughness in precipitation hardenable stainless steels.  Decreased toughness caused by prolonged exposure to high temperatures can be reduced by high temperature aging.

Corrosion resistance of V155 is pretty comparable to AISI304 and similar to AISI630. Stress corrosion cracking resistance is achieved by precipitation treatment at temperatures equal or higher than 550°C in order to provide lowest hardness compatible with the specific use.  V155 exhibits good erosion-corrosion resistance thanks to its corrosion resistance combined with the high hardness.

For better corrosion resistance surfaces should be clean, free of scale and residuals.  Passivation is recommended for fabricated parts.

Annealed condition is not suitable for applications or services.  Precipitation hardening after solution treatment is recommended in order to avoid delayed crackings.

Hot Working

V155 could be easily forged and hot-formed.  Before forging, material should be heated to 1180-1200°C for 1 hour.

Forging below 1000°C is not recommended.  In order to have material exhibiting best grain size and mechanical properties, forgings should be cooled in air to below 35°C before further processing.

Cold Working

The material could be moderately but not hardly formed in the overaged condition.  Best machinability or cold deformation can be achieved in the double-aged conditions (H1150M).

Weldability

V155 can be satisfactorily welded by conventional inert gas, shielded fusion and resistance processes because of Carbon pickup, preheating is generally not required to prevent cracking, while post-welding heat treatment is recommended to generate the precipitation hardening properties.

Material could be welded in the solution anneaed condition and can be precipitation treated to the requested hardness after welding; nevertheless, in order to minimise the effect of several thermal cycles, to have more uniform properties and to have best corrosion resistance in the aged material, solution annealing is suggested before precipitation treatment.  In case high welding stresses are expected, it could be better to weld in the overaged conditions (H1150); in this case, the component should be solution treated after welding and aged.

Should teh weld not exhibit high strength and austenitic stainless filler as E/ER308L has to bbe used. If welding has to provide properties similar to the ones of the base metal in the precipitation treated condition then E/ER630 filler metal is required in order to have the filler producing the precipitation hardening effect.

After the solution heat treatment material achieves UTS 680-690 N/mm², in this condition it can be cold-formed by standard processes.

Technical Data Sheets