Installation and welding process and problem handling of box shaped door slot

Abstract

The Qingyuan Pumped Storage Power Station is equipped with a tail water emergency gate in the tailrace tunnel. The emergency gate slot is a square steel lining structure, and the lining plate material is stainless steel composite plate(Q355B+06Cr19Ni10), with a thickness of 30 mm. The base layer thickness is 26 mm, and the stainless steel composite layer thickness is 4 mm. The outer structure of the lining plate is made of ordinary low alloy steel and carbon steel materials. The upstream and downstream of the gate slot are square interfaces, connected to the steel lining of the draft tube by welding, and the rest are closed structures. The operation mode of the tail water emergency gate is dynamic closing and static opening. The water retaining head of the gate is 128 m, and the water closing head of the dynamic water is 114 m. Based on the structural characteristics of the gate slot, a welding process plan has been developed, and the design of the composite plate welding joint for the gate slot has been improved. An improved welding process has been proposed for the elevation weld seam of the gate slot. The quality of the connecting weld seam of the gate slot lining plate meets the Class I weld seam requirements specified in the design, and the welding quality is good.

Keywords

box shaped door slot / stainless steel composite plate / weld