Ensuring maximum safety and cost savings were the sole considerations of one oil and gas contractor when it asked TWI to solve a problem.
The customer had built an LNG tank and installed associated pipework between 50 and 600mm diameter when, during commissioning, they detected ferritic contamination in the weld pipelines.
TWI was established on site within five days, and performed an inspection rate of 100 welds per day within the week.
The material was a 304L stainless steel. Simple inspection by the client using magnets revealed early on that some of the welds were ferritic material but magnets are not an entirely accurate way of positioning the flawed areas so the client came to TWI with a request to devise a technique using eddy current equipment to inspect for contamination. They wanted to be able to position the flawed regions accurately.
The client was quick to acknowledge that the contamination was not caused intentionally. Occasionally sub-contractors, unfamiliar with the specific requirements of a job, pick up the wrong consumable. TWI was able to identify the troubled regions on time and to budget to the satisfaction of the client.