Valves having high wear-resistance and high corrosion-resistance

A valve, including:

• a valve body;
• a valve case;
• a first valve seat disposed on sliding surfaces of the valve body;
• and
• a second valve seat disposed on a sliding surface of the valve case;
• wherein each of said first and second valve seats is constructed of a welded metal comprising at least one of:
• a Co base alloy, an Ni base alloy, and an Fe base alloy;
• wherein each of said first and second valve seats has a plurality of layers in a thickness direction, including:
• an inner layer with a dendrite structure, a middle layer with a processing structure, and a surface layer with a cubic structure, and a layer of base material;
• and
• wherein said surface layer of each of said first and second valve seats is formed by a base portion made of the cubic structure, wherein dispersed in the base portion is:
• a granular eutectic chemical compound having a grain diameter equal to or less than 100 μm, or a blocky eutectic chemical compound having a block diameter equal to or less than 100 μm.