A350 LF2 Valve Balls is suitable for low temperature environment -46℃。Normally with ENP plating.

ASTM A350/A350M LF2 Material specification

1.1 heat treatment

The forgings are quenched and tempered. After the forgings are completely austenitized by the quenching procedure, the forgings are then quenched in the appropriate liquid medium. The tempering procedure heats the forging to 590℃ for a sufficient time (30min/1in) for air cooling.

1.2 Smelting process

The steel shall be prepared by any of the following methods: open hearth furnace, basic oxygen blown converter, electric furnace or vacuum induction smelting (VIM).The primary smelting may be combined with a separate degassing or refining, or may be followed by secondary smelting using ESR or VAR. And shall be completely killed steel.

1.3 Chemical composition

A—Cr、 Mo、 Ni、 Cu maximum amount of elements is 1.00%；

B—Cr、 Mo maximum amount of elements is 0.32%。

1.4 Mechanical properties

1.5 the quality

The forging should have a good forged surface. Before the final surface inspection, all the oxide skin and machining burrs should be removed from the surface of the forging. During the process of removing the oxide skin, the surface finish, material properties or metallographic structure should not be damaged. For forgings showing scars, folds, tears, or cracks of less than 5% or 1/16 of an inch (1.6mm) of nominal wall thickness, removal of these defects is not necessary, but cutting or polishing should be used if removal of such defects is required.

2.Welding repair

The chemical composition of A350 has an important influence on the formation of crystal cracks during welding. During welding, impurities such as S and P in the welding seam form eutectic with low melting point in the crystallization process. Among them, S has the greatest influence on the formation of crystal cracks, but its influence is also related to the content of other elements in steel, such as Mn and S combine to form MnS to remove sulfur, thus inhibiting the harmful influence of S.Mn can also improve the performance, morphology and distribution of sulfide.Therefore, in order to prevent the occurrence of crystal cracks, certain requirements are required for Mn/S value in weld metal.

2.1 All rewelded forgings shall be heated to 590℃, but not higher than the original tempering temperature of the base material of the same forgings for stress-relief treatment or quenching and tempering treatment instead.