Federal-Mogul Powertrain has announced the introduction of new powder metal (PM) materials for valve seat inserts and valve guides. Said to offer improved corrosion resistance, higher mechanical strength and reduced costs compared to established cast materials, the new PM materials – which are applicable primarily to on-highway, off-highway and high power density leisure marine engines – can contribute to reduced CO2 emissions by enabling more efficient gas flow across the valve seat chamfers.
“The switch from cast materials to PM started decades ago in the light vehicle sector and we are now witnessing the same trend in heavy-duty engines while achieving better corrosion resistance, wear performance and great mechanical strength,” explained Gian Maria Olivetti, chief technology officer, Federal-Mogul Powertrain. “Currently PM materials have a market share of around 25% in heavy-duty and with widespread interest among customers, this is growing steadily.”
FM-S20B is Federal-Mogul’s new intake valve seat insert material. Road salt ingestion in developed markets and variations in fuel sulphur levels in developing regions both contribute to intake corrosion, as can condensation arising from increasing levels of exhaust gas recirculation (EGR).
FM-S20B uses a ferrous base, unlike comparable cast alloys which use a cobalt base. Federal-Mogul states that in tests during development, valve seat inserts made from FM-S20B displayed greater corrosion resistance than various grades of cast material.
For exhaust valve seat insert applications subject to high thermal and mechanical loads, Federal-Mogul Powertrain has developed FM-S33P, a wear resistant full-density material that combines cobalt and high speed tool steel. Available in trial production runs for prototype evaluation by heavy-duty customers, S33P has been tested successfully against cobalt-based T400 cast materials and Federal-Mogul Powertrain will undertake a test programme for application in CNG engines later this year.
FM-G15E uses a high volume of solid lubricant captured within a specially treated Molybdenum Nickel powder metal steel microstructure to reduce friction and resist wear. It is vacuum oil impregnated to give additional tribological support and provide a combination of machinability and durability.
“Federal-Mogul Powertrain’s PM valve seat inserts and guides were initially developed for hot automotive gasoline applications and heavy-duty diesels but they have also proven themselves in CNG-fuelled oil field power generation units, where hot, dry conditions without the lubricity of diesel soot can lead to accelerated wear with cast components,” commented Frank Zwein, Global Application Engineering Director, Valve Seats and Guides, Federal-Mogul Powertrain. “In engine trials, we have run more than 10,000 hours in this harsh environment, with low to zero measurable wear.”