THE THREE WAYS TO CONTROL SENSITISATION

For those who do not know of us, our speciality comes in the form altering tubing to suit a variety of specifications. With techniques such as tube expansion we are able to alter tubes so that they can fulfil their intended purpose. With state of the art equipment suitable for working on a variety of materials, we have the potential to meet a multitude of requirements. As far as welding stainless steel tubing goes, there’s no magic involved. All it really takes to make certain that the final product meets the necessary quality standards and maintain its corrosion resistant characteristics is the right selection of joint preparation, welding operations and filler metals. The quality of the weld is important if you are going to do any tube expansion, bending, or other adaptations. As the years have gone by, a number of well-established methods have evolved, enabling fabricators to amplify productivity without offering up the steel’s corrosion properties. This has also helped to assist in boosting the quality when it comes to adapting the tubing. The main cause of the loss of corrosion resistance is sensitisation, which is affected by the chemistry of the filler metal and base substance, not to mention the temperatures at which your weld cools. Chromium oxide acts as the stainless layer of the steel. If the carbon levels are strengthened in your weld and neighbouring heat affected area, chromium carbides are formed. These tie the chromium up and stop chromium oxide from manifesting, permitting the steel to corrode. One can counter sensitisation in three ways. Your first choice is to use a low filler metal and base to diminish or get rid of the carbon completely during the weld. The second option is to minimise the time that the heat affected area and weld are at temperatures that are advantageous to sensitisation. Finally, you can utilise filler metals that possess unique alloying components to halt the formation of the chromium carbides. At Multiform we make use of only the most effective techniques and strategies when working on your tubing. What tube expansion consists of exactly is using a myriad of approaches to open the tube’s end section, giving it a plethora of uses and providing a snug, leak proof fit onto other tubes at the same time. We can provide this service on a myriad of materials, including stainless steel. If you would like to find out more about what we can offer you, feel free to contact our team.