One Minute Mentor: Maps of Wear Resistance
November 27, 2017 Source: ASM International
The images show wear maps for (a) treated and (b) nontreated 316 stainless steel. The T316 stainless steel was treated by low-temperature carburization.
Continue readingOne Minute Mentor: High-Temperature Nitriding for Deeper Case
March 2, 2017 Source:
High-temperature nitriding or solution nitriding at temperatures of 2010 ± 90°F is a new treatment available to produce cases with nitrogen concentrations in the range of 0.4 to 0.9 wt%, which is low compared to plasma nitriding treatments at low temperature (up to 16.9wt% N), but the resulting case is up to 100 times deeper (2 mm, or 0.08 in.). The lower nitrogen concentration implies a lower surface hardness (360 HV for solution nitriding of austenitic steels).
The graph shows a time-temperature transformation (TTT) curve for the precipitation of Cr2N, from which it can be estimated that, to avoid CrN precipitation, the temperature must drop from 2010°F to below 1650°F in approximately 20 seconds. That is feasible only in relatively thin parts (large area/volume ratio) that cool sufficiently to cope with the TTT curve time limitations to avoid precipitates, and only for a small number of parts at a time.
Volume 4D, Heat Treating of Irons and Steels ⇒ Heat Treated High-Alloy Steels ⇒ Nitriding of Stainless Steels ⇒ Thermochemical Nitriding Treatments
High-temperature nitriding or solution nitriding at temperatures of 2010 ± 90°F is a new treatment available to produce cases with nitrogen concentrations in the range of 0.4 to 0.9 wt%, which is low compared to plasma nitriding treatments at low temperature (up to 16.9wt% N), but the resulting case is up to 100 times deeper (2 mm, or 0.08 in.).
Continue readingOne Minute Mentor: Secondary Hardening in Tool Steels
January 22, 2016 Source:
As shown schematically in the graph, high-temperature hardness is made possible only by a very important straightening mechanism: secondary hardening, promoted by the precipitation of fine alloy carbides. The stronger the secondary hardening (meaning more intense carbide precipitation), the higher the tempering resistance of hot-work tool steels. Such precipitation intensity depends on the amount of alloy elements in solid solution, which is related to the alloy composition and heat treating practice obtained by molybdenum, vanadium, or tungsten alloying.
The graph shows a schematic of hardness after tempering and the effect of secondary hardening in high-alloy steels. Observe that high-temperature hardness is only possible through precipitation hardening caused by alloy carbides (secondary hardening). At low temperatures, hardness is less than martensite due to the presence of retained austenite, which is eliminated after high-temperature tempering.
Volume 4D, Heat Treating of Irons and Steels ⇒ Tool Steels ⇒ Heat Treating of Hot-Work Tool Steels ⇒ Introduction
As shown schematically in the graph, high-temperature hardness is made possible only by a very important straightening mechanism: secondary hardening, promoted by the precipitation of fine alloy carbides.
Continue readingHeat treat 2015 finishes with a “bang!”
November 2, 2015 Source:
The ASM Heat Treating Society Conference and Exposition (Heat Treat 2015) took place in late October in Detroit. The three-day event, co-located with the American Gear Manufacturer's Association Gear Expo, attracted over 7000 heat treating and gear professionals from all over the world, including an equipment exhibition featuring 202 companies in 288 booths. The show featured top-notch technical programming as well as several new initiatives such as live equipment demonstrations on the show floor and a "hot" new social event that lit up the Detroit sky as well as local social media.
The technical program at Heat Treat featured more than 140 oral and poster presentations, including a new Applied Technology track focused on practical applications for operators. Jonn Nebbe, a metallurgical engineer at Eaton Corp., said, "Learning about the academic side of things is nice, but learning practical applications that you can take back to the shop floor? That's what I'm here for."
Attendees also enjoyed a plenary session from Dr. Alan Taub, chief technical officer of the newly established American Lightweight Materials Manufacturing Innovation Institute, who discussed the LIFT (Lightweight Innovations for Tomorrow) consortium. The conference program also featured an expert-led panel on "New Development and Opportunities in Heat Treating" focused on technology needs and new disruptive technology within the industry. Finally, the popular Master Series lectures educated attendees on specific technical subjects such as the past and future of martensitic steels, bainite transformation in steel, and the Holloman-Jaffe parameter.
Local high school students got to participate in the ASM Materials Education Foundation "Mini Materials Camp" on the show floor during Heat Treat. Eight presenters gave hands-on science demonstrations to over 150 students in the mini-camp, including heat treating bobby pins and paper clips and the principle of diffusion at work in brassing a penny. College students also took part in the free "This is Heat Treat" student program, which included a special 35 and Under Keynote Breakfast and a student networking mixer on the show floor.
On the networking side of the event, attendees had many opportunities throughout the week to meet and catch up with old friends. Exhibitors and attendees were treated to a networking reception on Tuesday evening featuring local brews and appetizers on the show floor, and several refreshment and dessert breaks throughout the week. The main event however, the first-ever Heat Treat social event called "The Heat Is On," was held Wednesday evening at Waterview Loft at Port Detroit. Guests were treated to flame twirlers, local craft beer, and Detroit-style food. The evening was capped off by a fireworks display on the Detroit River, which surprised both guests and locals who happened to catch the show. The "mystery" fireworks caused quite a stir on social media and the news.
Attendees, exhibitors, and sponsors were positive about the direction that Heat Treat is going. "There is a new energy to this event," says Stephen Kowalski, president of the ASM Heat Treating Society and president, Kowalski Heat Treating. "The organizers are doing some exciting things with the programming, and the social event really was above and beyond all expectations and certainly had the local and international media on fire. Even if you have been to Heat Treat before, come again in 2017 – you won't be disappointed."
Chuck Faulkner, Market Development Manager, Heat Treatment & Metal Forming at Houghton International, says that Heat Treat is the must-attend event for the heat treating industry. "This show is one our company doesn't miss. We will be back in 2017."
Heat Treat 2017 will take place in Columbus, Ohio, on October 24-26, 2017. Space is limited and is expected to sell out. To reserve exhibit space, contact Christina Sandoval, global exhibition manager a [email protected] or 440.338.5151 ext. 5625.
The ASM Heat Treating Society Conference and Exposition (Heat Treat 2015) took place in late October in Detroit. The three-day event, co-located with the American Gear Manufacturer’s Association Gear Expo, attracted over 7000 heat treating and gear professionals from all over the world, including an equipment exhibition featuring 202 companies in 288 booths.
Continue readingUltra 76 Plus tantalum alloy resists corrosion in hot concentrated acids
July 8, 2015 Source:
H.C. Starck, Newton, Mass., introduces the Ultra 76 Plus tantalum alloy, which is designed to combat aggressive hazardous-chemical corrosion in hot concentrated acids. The alloy is based on the Ta2.5W alloy, which improves corrosion resistance by minimizing hydrogen embrittlement, extending equipment life, and reducing downtime.
Ultra 76 Plus was designed by H.C. Starck's Fabricated Products Division. It enables increased concentrations and operating temperatures in HCI, H2SO4, and other acids. It can add value to a multitude of products, from heat exchangers, condensers, and coils, to thermocouple protection sheaths, pumps, distillation columns, boilers, and condensers.
H.C. Starck's high-tech materials — molybdenum, tungsten, tantalum, niobium, and their alloys — are excellent choices for applications in high temperatures and severe environments. Tantalum, in particular, is widely used in electronics, chemical processes, and biomedical industries, where its alloys provide cost-effective, long service-life solutions for mission-critical components. In addition, it enables users to eliminate separate "Platinum Spot Welding" steps.
H.C. Starck, Newton, Mass., introduces the Ultra 76 Plus tantalum alloy, which is designed to combat aggressive hazardous-chemical corrosion in hot concentrated acids.
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