Steel bridge girder fabrication capabilities.

Unit 1, Domjur, holds RDSO approval under Part A for the fabrication of open web, composite and other steel plate girders. The units fabricate in both mild steel and stainless steel. Unit 1 has 150,000 sq ft of floor area, and the company has a team of over 200 workers. Cutting, assembly and welding follow the customer’s drawings and the quality assurance plan written for the job. Builds include the bridge girder assembly for Eastern Railway and the 50 m road bridge for the Government of Sikkim.

• CNC plasma cutting of plate
• Material bending and rolling
• MS and SS fabrication and assembly

The company profile lists precision machining and assembly of steel structures among the works’ experience, with expertise for high-precision jobs and a specialised team of engineers for high-precision fabricated items. The customer’s drawings and the quality assurance plan written for the job set which parts are machined, and to what tolerance. Send the drawings with an enquiry and the works will confirm how each part is made. More detail is on the engineering capabilities page.

• Machining alongside fabrication, in one works
• Parts and tolerances to the customer’s drawings
• A specialised team for high-precision items

The QAP lists the checks for each stage of the girder. Where the railway or the client sends its own inspection protocol with the drawings, the girders are checked to that protocol as well. The QAP names the inspection methods, the acceptance criteria and the records kept. Each check is documented, and the quality records go to the client on request. Unit 1, Domjur, runs an ISO 9001 quality system, and the same QAP discipline runs across the whole works.

• A quality assurance plan for each girder order
• Stage-wise inspection through fabrication
• Quality records on request

Stress relieving heats a welded component to the set temperature, holds it there for the soak time and cools it at a controlled rate. This eases the residual stress welding leaves in the steel, so the part keeps its shape in machining and in service. The customer’s specification and the quality assurance plan written for the job decide which girder components need it. The cycle is the same one used across the works.

• Temperature, soak time and cool-down to the specification
• Controlled cooling after the soak
• Only where the specification calls for it

Blasting takes the rust and mill scale off the steel, so the first coat bonds to clean metal. Moisture is kept down because damp steel weakens that bond. The paint system, the number of coats and the checks follow the customer’s specification and the quality assurance plan written for the job. The primed through-truss girder in the photograph has been through this stage and is ready for dispatch from the yard. Surface preparation and painting are among the facilities in the company profile, and the same blasting and painting serve both divisions.

• Copper slag, grit or sand blasting to specification
• Spray or airless painting
• Paint system to the customer’s specification