Companies Introduce New Product Line at Power-Gen

Atwood & Morrill Co., Inc., Salem, Mass., in conjunction with Hopkinsons Ltd. Huddersfield, UK, announces a new complete range of engineered valves including Parallel Slide Gates, Wye Globes and Checks in modified 9 percent chrome steel.

Modified 9 percent chrome steel cast valves are fully compatible with power plant designs specifying P91 pipe and T91 tube materials to minimum piping system costs. They offer same P group welding procedures and resistance to thermal fatigue with reduced weight. Modified 9 percent cast chrome is pound for pound twice as strong as conventional CrMo steel at high temperatures and is suitable for high temperature steam cycles. The advantages of modified 9 percent chrome include:

• Reduced piping component weight and reduced hanger and structural support system size
• Increased life of piping and valves by minimizing thermal fatigue cracking
• Higher steam temperature allowed for greater thermal efficiency

Hopkinsons has 10 years experience with modified 9 percent chrome steels in power plants. Using their in house foundry and engineering capabilities, Hopkinsons has optimized the design of cast modified 9 percent chrome valves. Analytical studies have shown cast steel valves in modified 9 percent chrome are 35 percent more resistant to creep damage than similar valves constructed from 21/4' Cr I percent Mo steel. Forged valves constructed from F91 steel do not have the advantage of smooth contours and transitions found in engineered castings, and are more susceptible to creep damage. Hopkinsons has manufactured a wide range of cast valves in modified 9 percent chrome steel, currently installed in power plants in Europe, the United Kingdom, China and Australia.