Electric Resistance Welding(ERW) Pipe

Lonrace uses the Electric Resistance Welding(ERW) process to obtain a continuous longitudinalseam weld on the tube it produces. This process depends on a number of important factors to ensure a complete weld. The most important of these factors are:

• Strip width size

• Strip preparation through the mill forming and finpass stand

• Induction of current in the strip and concentrationof the current and resulting heating of the steelalong the strip edges.

• Presentation of the strip edges at the tube mill weld stand

• Squeeze out of the resultant molten metal.

 

Strip Preparation Welding Each size of tube produced has its own unique strip width.

The strip width is calculated using various parameters including, finished tube size, tube wall thickness,radius of corners desired (for square andrectangular tubing) and theoretical squeeze out ofmolten metal at the weld head. 

 

Lonrace purchases steel coils from primary mill sources and slits the coils to width on its own slitters in-house. The strip width is controlled to +/- 0.020inches.

An integral part of obtaining a sound weld is to ensure the strip edges are prepared properly prior to welding. This is accomplished by passing the strip, which is by this time partially formed into around section, through a series of rolls called fin passes. The fin passes are designed to burnish the strip edges to clean them for welding and to ensure the edges are beveled to the proper angle to allow the strip edges to come together evenly. The strip edges must meet in such a manner that there is no gap at the top (outside of the tube)or bottom (inside of the tube). This ensures an even amount of extrusion, or squeeze out at the weld head (sometimes referred to as weld pressure rolls)and without mismatch. Mismatch occurs when one strip is higher or lower than the other when the two edges meet. 

 

After the molten metal is extruded out of the weld area it is cut from the outside and if required theinside of the tube to leave a smooth surface. A “first off" the weld is inspected at each set up.The characteristics inspected are the amount of extrusion, the presentation of the strip edges,and complete bonding of the strip edges.

 

All tube mills require a minimum level of equipment to accomplish the basic task of producing tube. The entry section of a tube mill will feature some means to unroll the strip from its coil form, and a way to join the end of the last coil to the beginning of the next. All tube mills will feature a series of tooling to form the strip into tube, and a welding station to join the seam of the tube, followed by some method for cutting the tube to length. Some mills feature additional equipment to make the operation more efficient, or to add special features to the tube. The headings that follow identify the equipment common to most tube mills, as well as some of the specialty equipment that may also be featured on a particular mill.

Jiangyin Lonrace International Trade Co., Ltd. is a leading company which specialized in dealing with various kinds of boards, ceilings and steel pipes in Jiangsu Province, China. Our company brings in advanced testing & production equipment to guarantee quality precisely.

With our policy of “Quality first, Customersprior and Price reasonable” we have established good relationship with the customers all over the world.

Customers and friends are warmly welcome to contact and cooperate with us.

 

Which port can you support?Answer: Shanghai Port or Tianjin port or any other China port you need. If provided destination port, CFR and CIF can be quoted for your reference.2. What's your delivery time of your products?Answer: Usually it takes about 10-15days after receiving the advance payment to send out the goods by sea or air.3. What about the terms of payment? Answer: Most customers choose 30%TT advanced payment, balance against copy of BL.Other terms of payments ways like LC or DP also can be negotiated.For small orders, paypal and westunion also available.4. What's your Minimum order quantity(MOQ) of your product?Answer: Most customers choose 1x20"GP as trial order. Small orders are also accepted.