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'Mildly sour' environment project saves half a million pounds

Back to Pre-1998 Articles Adhesive technology demonstration centre Aged samples lend added credence to safety codes Arc welding Demonstration Centre shows best practice in action Boiler takes the heat in comfort Conductive adhesive for ultrasound catheter cracking-risk-in-steel-pipelines-from-external-hard-zones Engineering critical assessment of pipeline welds Far East fitness-for-purpose check First UK Research Council contract for TWI Friction stir welding of titanium Help with adhesives training Joining demonstration centres in industry Joining Forces success in Belfast Joints take 10 seconds in the microwave LIVEMAN - Advanced joining processes for lightweight vehicle manufacture Making calculations easier 'Mildly sour' environment project saves half a million pounds New standard for weld fracture toughness testing Novel method joins plastic pipes Plastics fume - new findings released Project saves time and money for Amerada Hess Small firms seize no-cost reviews and low-cost trials South East Asia ACFM course Space Shuttle technology transferred to power generation industry Spot the evidence Structural integrity assured for Liverpool Bay Supporting technology on the Indian sub-continent Technology demonstrators show best practice in action Thermomechanical material processing by friction [friction pillar processing] 'Tubestress' measures residual stresses in parts that other equipment cannot reach TWI enhances on-stream inspection service Underwater welding work expands at TWI North Wider recognition for welding inspectors

Mildly sour environment project saves half a million pounds

Connect, no.76, May 1996


The results of a major TWI project are already helping the oil and gas industry to cut costs. One operator has saved about half a million pounds by demonstrating fitness-for-purpose using current data.

The project, sponsored by a group of companies, evaluated safe hardness levels for welded C-Mn and low alloy steels exposed to mildly sour environments.

The work showed that hardness levels above 22 HRC equivalent can be tolerated in many environments up to at least ten times the NACE MR0175 limit of 0.05psi partial pressure H2S, depending on other environmental variables, most important of these being pH.

The results are in general agreement with recent EFC guidelines, but there are important differences in specific hardness limits recommended. Furthermore, an effect of total system pressure was noted in this work, which is believed to be the first major programme in this area to have been carried out at elevated pressure (mostly 500psi).

In view of the very significant potential financial and safety implications of these findings, the Sponsor Group has decided that the database should be strengthened. Further work, concentrating on the effects of total system pressure and ambient temperature is now proceeding.

Any new Sponsors participating in this further work will receive the final report for the first programme, (total value greater than 400 000 pounds) for no additional cost.

For further information on this excellent value joint-funded deal, contact Richard Pargeter:

For more information please email: