Welcome to BJ Welding

BJ welding is specialized in design and manufacturing of steel structure buildings, mining process equipment, food process equipment and customer made equipment according to the customer needs from small project to large and complicated projects.

welding

Our main products include

Steel structure warehouse and workshop, Large industrial building, Sliding Gates, Pedestrian/Security Gates, Burglar Bars, Fencing, Pool Fencing, Balustrades steel, Railings, Driveway Sliding Gates, Pedestrian Gates, Panels, Fencing Panels, Railings, Garage Doors, Benches, Tables, Chairs, Bird Cages, Gate Tracks any items that fit this general design.

Whether it's Steel structure or other custom process equipment, make BJ Welding your first call for a quote.

Our highly trained team of engineers, welders and fitters have built equipment for every kind of process industry, and with over 100 welding procedures, we can work with a variety of materials.

NB: BJ Welding slogan “If it can be shipped, we can build it”.

For years now, BJ Group has been the fabricator of choice for various equipment design, and end users across Africa for their customer process equipment. Let us quote your next project!

BJ Welding can take on your engineering requirements and be your one-stop shop for design and fabrication.

Projects continue to get more complex, while timelines get shorter.  Our engineering capabilities give clients the ability to outsource as much of the design phase as desired.  Our engineering team can execute projects faster and at lower total cost by optimizing your design for fabrication.

Our specialty welding products are manufactured with the highest quality raw materials including; stainless, Mild Steel and Aluminum and copper. Our products fulfill the specific, filler needs of many technical processes, including shielded metal arc welding (SMAW), submerged arc welding (SAW), tungsten inert gas welding (GTAG), flux-cored arc welding (FCAW), and gas metal arc welding (GMAW​

All Welding products are supplied with a certificate of conformance stating physical and mechanical properties including alloy chemistry. Every welding product is manufactured to have its own unique lot identification number for full lot traceability.

 

Professional Welding service heavy design factory

Steel structure features

1. Design according to customers’ requirements

2. Manufacture under complete quality control system---ISO9001

3. Installation with instruction of experienced engineers

4. Easy to assemble and dismantle

5. Environmental protection material: can be used for several times and can be recycled

6. Shorter construction period, longer using time

7. High strength and stiffness, high weight bearing.

 

Welding Deformation Of Steel Structure

Welding of steel structure welded steel structure is widely used, and full penetration welding is used for some important welds. In the process of local heating and melting during metal welding, the temperature of the metal in the heating zone is very different from that of the surrounding parent material, resulting in instantaneous stress in the welding process.

After cooling to the original temperature, the tensile stress zone of the whole joint area and the near seam area is in balance with the value of the mother material in the compressive stress zone, resulting in the welding residual stress of the structure itself.

At this point, the welding joint structure takes many forms of deformation under the action of welding stress. The existence and deformation of residual stresses are mutually transformed, and it is not difficult to find a way to prevent and correct the deformation.

 

Forms and causes of welding deformation:

The deformation of steel structure after welding can be divided into two kinds: the deformation of the whole structure and the deformation of the structure. The deformation of the whole structure includes the longitudinal and transverse shortening and bending of the structure. The local deformation is convex, wavy, angular deformation and so on.

 

Common basic forms of deformation.

The basic forms of common welding deformation are as follows: the length of the plate groove is shortened (longitudinal shrinkage) and the width is narrow (transverse shrinkage); The Angle deformation after butt welding of plate groove;

The distortion of the angular deformation along the longitudinal direction of the component along the longitudinal axis of the component and the longitudinal contraction of the component flange and the web is distorted.

The wave distortion formed by the buckling of the plate surface due to instability due to the instability of the pressure zone of the laminates. Due to the longitudinal and transverse contraction of the weld, the integral bending of the component is caused by the asymmetry of the neutral axis of the component, and this deformation is bent.

 

Reasons for welding deformation:

  • In the welding process, the partial and uneven heating of welding parts is the cause of welding stress and deformation. Near the welding seam and the weld metal is heated area expansion, due to a cold metal stop this expansion, occurs in welding area compression stress and plastic shrinkage deformation, has a different degree of transverse and longitudinal shrinkage. Due to the contraction of these two directions, various deformation of welding structure is caused.
  • The longitudinal shrinkage deformation of the welding seam is compensated by using the component reserved length method.
  • To minimize the number and size of welds in design; Reasonable layout of the weld, in addition to avoid the weld density, should also make the weld position as close to the axis of the components as possible, and make the weld layout and components.
  • Select the welding sequence correctly. In the steel structure, when there is a weld and fillet weld, in principle, the weld shall be welded to the weld and the arc weld. For the cruciform and t-type welds, the correct order should be taken to avoid welding stress concentration and ensure the welding quality of joints. It is advantageous to reduce deformation by adopting the welding of the neutral axis of the whole steel structure and taking the welding from the middle phase. Welding of important parts in steel structure with high strength should be free to contract and not be restrained

 

Construction Technology of Steel Structure

Applicable scope: is suitable for construction steel structure processing production process, including the selection of process flow, layout, marking, cutting, straightening, molding, edge processing, tube ball hole processing, the system, the friction surface processing, end processing, assembly of components, assembled pipe processing components and steel members.

 

Material Requirements

  • The steel, welding materials, coating materials and fasteners used in the steel structure shall have a quality certificate, which must conform to the design requirements and the current standards.
  • Raw materials into the factory, besides must have a factory quality certificate, and shall be in accordance with the contract requirements and the current standards in the testimony of party a, supervision, on-site witness sampling, deliver, inspection and test, inspection records. And provide inspection report to party a and the supervisor.
  • In the process of processing, if the raw material is found to be defective, it must be investigated by the inspectors and the competent technical personnel.
  • The material substitution shall be submitted by the manufacturer in advance with the application for the certificate of materials (technical verification sheet), and after the examination of party a and the supervisor, it shall be confirmed by the design unit before it can be used.
  • It is strictly forbidden to use the solder with the peeling or rust of the core, the dampness or the melted flux and the rusty wire. It is used for bolting studs, and the surface shall not have any defects such as cracks, striations, dents and burrs.

 

Operating conditions

  • Complete the construction details and sign the approval by the original designer.
  • Construction organization design, construction plan, work instruction and other technical preparations are ready.
  • Various process evaluation test and process performance test and material purchase plan have been completed.
  • Main materials have been entered into the factory.
  • All kinds of mechanical equipment debugging, and acceptance are qualified.
  • All the production workers shall be trained before the construction and obtain the qualification certificates.