UGI® 4542 H1150D

UGI® 4542 is suitable for:

UGI® 4542 offers excellent corrosion resistance, similar to that of type 18 Cr-8Ni austenitic steels in most corrosive environments. The structure of this steel makes it insensitive to intergranular corrosion and highly resistant to fatigue-corrosion as well as to stress corrosion. Furthermore, excellent resistance to corrosion-erosion should be noted due to the association of high level mechanical properties and corrosion resistance. When assemblies of stainless steel and less noble materials (aluminium, mild steel) are applied in atmospheric use, there is no risk of galvanic corrosion, the absence of any environmental electrolyte making it impossible for this phenomena to develop and spread. In "critical" cases like those met in nautical applications (short term immersion of stainless steel/aluminium assemblies, areas and dips that retain liquids), insulating the assemblies using an inert silicon seal offers good results in terms of protection against this kind of corrosion.

If necessary, the following decontamination treatment process is recommended:

The corrosion resistance of a stainless steel depends on many factors related to the composition of the corrosive atmosphere (chloride concentration, presence or absence of oxidising agents, temperature, pH, agitation or no agitation, and so on), as well as to the preparation of the material (surfaces free from metal particles, surface finish, such as hardening, polishing, and so on). Precautionary measures should be taken for certain tests such as the saline mist test (French standard NFX 41002): for example marking labels (that might cause corrosion run-outs and reduce the test resistance time) should not be used on the sample. The table below illustrates a performance scale in different environments:

To ASTM A564/A564M and EN10088-3

After annealing from 1030°C to 1050°C, UGI®4542 presents a soft martensitic structure with a hardness of around 35 HRC. After annealing, if the metal is to be used in this condition, we recommend an expansion treatment lasting one to two hours at 250/300°C, with no significant effect on its mechanical properties.

This precipitation hardening steel is specific in that it can be hardened, after annealing, using a medium temperature hardening treatment. The maximum hardness, of around 42 HRC (impact strength of 3 daJ/cm²) is obtained by tempering to around 480° C (for one hour).

Softening: by tempering at 550-760°C depending on the instructions defined by the applicable standards. To harden the metal after this kind of softening, the metal needs to be annealed once again before performing the medium temperature hardening treatment.

The annealed bars are suitable for medium temperature hardening, performed on parts. Parts taken from softened bars must, to harden, be subject once again to an annealing operation, then to the medium temperature hardening treatment.

UGI® 4542 is suitable for forging. Reheating takes place between 1150 and 1200°C, forging between 1200°C and 950°C. Cooling in air, water or oil. The parts obtained in this way can be used:

Available products:

UGI® 4542 can be welded, without preheating, using MIG and TIG techniques, with or without the use of filler material, or by laser, resistance or electron beam techniques.

Welds, whether made with or without a filler material, have an annealed structure and should preferably be subject to expansion treatment (one to two hours at 250°C/300°C) or hardening or softening treatment (see above).

For welding performed with no filler material or with a homogeneous filler material, the welding mechanical properties obtained in this way can be identical to that of the base metal.

Furthermore, it should be restated that the welding design should make allowance for the care required with all high steels with high proof stress: avoiding cut outs and sudden changes in cross section.

Welding with a filler material: For MIG welding, we recommend the use of a protective gas made up of Ar+1%CO₂ or 1-2%O₂; gasses containing H₂ and N₂ should be avoided. The welding wire used as filler metal can be ER308LSi (1.4316) or a homogeneous filler called 630 (17-4PH)