Fisher Barton is a materials company that uses unique, patented metallurgical processes to develop the most cost-effective solutions and to provide innovative design assistance to our clients. We effectively design and develop forage harvester blades, lawn mower blades and other agricultural blades and knives to fit the needs of our customers.

Marbain^®

We’ve developed an exclusive, proprietary and patented heat-treat process known as Marbain^® , which as the base material component production provides many advantages to our customers looking for alternatives to using Abrasion Resistant steel. Our understanding of the metallurgy of the raw material we use allows us to develop manufacturing practices and process improvements, leading to lower costs for customers’ product lines.

Austempering vs. Conventional Quench & Temper

The conventional quench and temper process, summarized in the isothermal transformation diagram produces martensite (BCT), a low density, hard, and very brittle phase. There are two factors that can cause quench cracks during the formation of martensite:

• reduced plasticity at low temperatures and
• instantaneous shear characteristics of the transformation.

Because martensite is not ductile at low quench temperatures and because of its rapid shear formation nature, the continuing transformation of austenite (FCC) to martensite (BCT) sets up very high stress factors in the initially transformed martensitic structure. When the martensitic phase can no longer absorb additional expansion stresses, cracks (macro and micro) can occur.

The Fisher Barton austempering process provides a solution to the expansion problems inherent with conventional quench and temper heat treating. Austempering produces its hardened structure (bainite) gradually and at a relatively high temperature, which provides many advantages:

• First, bainite’s slow nucleation and growth allows the transformation stresses to dissipate (20-minute bainitic reaction versus instantaneous martensitic reaction).
• Second, there is an increased plasticity resultant from the relatively high temperatures in the bainite transformation stages.
• Third, a smaller volume change is associated with the transformation to bainite. Further, bainite is more ductile than untempered martensite.

The Fisher-Barton Group. Five independent companies working together to offer our customers a broad mix of metallurgical expertise that results in superior, cost-effective components. Please contact us online for more information or call us at 920-206-4177.