Method of manufacturing a pressure vessel for growing single crystals

A method of manufacturing a pressure vessel for growing single crystals, comprising:

• preparing a pressure vessel body made of a heat resistant alloy for maintaining a supercritical state, the pressure body including an opening;
• preparing a corrosion-resistant mechanical lining provided on an inner face of the pressure vessel body and on an entire outer circumferential edge of the opening, wherein the corrosion-resistant mechanical lining is composed by joining the corrosion-resistant mechanical lining formed on the outer circumferential edge of the opening and the corrosion-resistant mechanical lining formed on the inner face of the pressure vessel body, a joining portion of which being distant from a corner portion of the corrosion-resistant mechanical lining;
• coating one or both of the inner wall of the pressure vessel body and the outer wall of the corrosion-resistant mechanical lining with ductile material;
• providing a hole for deflating gas staying between the pressure vessel body and the corrosion-resistant mechanical lining to the pressure vessel body;
• incorporating the corrosion-resistant mechanical lining into the pressure vessel body,
• removing gas staying in a gap formed between the pressure vessel body and the corrosion-resistant mechanical lining through the hole;
• sealing the opening by a cover under a condition that the corrosion-resistant mechanical lining formed on the outer circumferential edge of the opening is used as an airtight mating face;
• pressuring in the pressure vessel body and deforming the corrosion-resistant mechanical lining so as to closely contact the corrosion-resistant mechanical lining with the pressure vessel body;
• and
• cladding the corrosion-resistant mechanical lining and the pressure vessel body with each other,
• wherein:
• the joining portion is located on the inner face of the pressure vessel body;
• the corrosion-resistant mechanical lining includes a first portion formed on the inner face of the pressure vessel body having a first wall thickness and a second portion formed on the inner face of the pressure vessel body having a second wall thickness;
• the first wall thickness is greater than the second wall thickness;
• and
• the first portion is closer to the opening of the pressure vessel body than the second portion.