EXPLORATION • DRILLING • FIELD SERVICES
Plasma nitriding greatly benefits oilfield OEMs
Pulse plasma nitriding improves wear resistance, corrosion resistance and reduces frictional coefficient for critical OEM components used in oilfields
PLASMA THE POWER OF
n the harsh, corrosive and abrasive environments common to oilfield drilling and exploration, OEM products such as seamless steel tubes, valves and pusher or pipeline connectors are used. For such extreme operating conditions, case- hardening of carbon steel, ferritic stainless steel, austenitic stainless steel or Inconel is often a design requirement. To that end, nitriding and nitrocarburising have been the surface treatment of choice for decades. With today’s highly engineered parts, designers are increasingly turning to advanced plasma nitriding for more precise control of the diffusion layer formation, depth of hardening and preservation of component dimensions. Sophisticated electronics and software provide superior control for the DC pulsing signal, along with improved chamber design and construction. Tis enables more precise temperature control and uniform distribution of the heating zone throughout the hot-wall chamber. Te result is
I 12
www.engineerlive.com
extremely consistent and uniform nitriding, batch-to-batch, with less gas consumption than traditional gas nitriding. “Te benefits are more precise control of the diffusion layers and the ability to heat treat more diverse materials beyond steel that include stainless steel, titanium and even aluminium,” says Tomas Palamides at PVA TePla America. As a result, oilfield parts producers
have the capability to manufacture parts with enhanced properties such as higher wear resistance, improved corrosion resistance and reduced coefficient of friction. In addition, manufacturers and process engineers can now select from multiple system configurations, and process recipes, that offer flexibility, efficiency, and repeatability.
TECHNICAL ADVANTAGES With recent advancements in pulse plasma nitriding, a new level of precision and control is possible, which results in more
uniform and consistent case hardening. Together with the advantages of using only environmentally friendly gases, plasma- based nitriding has become a focal point for additional innovations, and a requirement for those that seek a safer, more eco-friendly solution. In PulsPlasma nitriding, parts are
processed in a heated vacuum chamber. After loading the parts on a supporting fixture, a bell chamber is used to cover the fixture, and the chamber is evacuated to below 10 Pascals. Te process begins by energising a generator that pulses a DC voltage of several hundred volts between the charge load (-) cathode and the chamber wall (+) anode. Process gases are gradually added in the chamber which are subsequently ionised and become electrically conducting. For pulse plasma nitriding a gas mixture of nitrogen and hydrogen are typically used, and methane can be added should a nitrocarburising process be sought.
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52
