Vacuum heat treating is a crucial step in the additive manufacturing process cycle to meet required part quality specifications.

Emissivity is a term used to define the ability of a surface to emit and absorb radiation. At any given temperature, the emissivity of a body (or surface) equals its absorptivity. Development work on a vacuum carburizing process revealed the need to better understand the effect of workload surface emissivity and the proper use of dummy thermocouple test blocks. This article reports on the findings from this research effort.

Understanding detrimental alpha case formation during heat treatment of titanium parts is increasingly important as titanium use in aerospace and medical applications continues to grow.

A novel hot zone design featuring new graphite boards reduces heat loss and improves overall hot zone power requirements.

Integral quenching (IQ) is a widely adopted heat treatment technique known for its efficient and rapid quenching capabilities. Vertical vacuum IQ furnaces give heat treaters a larger working zone for efficient and rapid quenching. This article describes the elements of a vacuum IQ furnace line and describes its operational workflow and process control.

This article reviews steps to improve the cost and efficiency of electrical heating methods for vacuum furnaces based on recent technology developments. Topics addressed include improvements in durability and efficiency of industrial power supplies and digital power supply diagnostics.

Residual gas analysis shows that vacuum furnaces with graphite hot zones are more economical than all-metal designs and are capable of producing contamination-free surfaces.

Temperature measurement, unvented cavities, loose powder, and direct contact of certain metals must be considered during process development for vacuum heat treatment of additively manufactured parts.

Successful part brazing relies on proper joint design, part cleanliness, and correct fixturing of part assemblies. Routine furnace maintenance allows repeatable, quality brazing results over time. This article describes aluminum brazing processes and process control considerations.

Heat treaters are discovering new opportunities in the rapidly expanding field of additive manufacturing. This article describes some of the opportunities and challenges for heat treaters in this technology area.

Vacuum solution nitriding is a promising technique for increasing the surface hardness, load-bearing capability, and fatigue strength of martensitic stainless steels without sacrificing corrosion resistance. This article examines the effects of nitriding pressure and temperature on surface nitrogen content and case depth in four martensitic stainless steels.

Stringent pressure control and gas species type both play an important role in minimizing the evaporation rate of not only copper, but other elements susceptible to evaporation in vacuum systems. The article describes a study investigating the effect of temperature, pressure, and carrier gas species on the amount of copper evaporation that occurs from copper foil test samples in low pressure carburizing.

New methods evaluate steel hardenability in a standard gas quench test and heat transfer coefficient variation within a furnace gas quench chamber.

This article compares heat treat processes and furnace types that are typically used to harden gears.

Active metal brazing played a key role in the development and fabrication of a modified beam target for particle-physics experiments conducted by Fermilab. The new target consists of a titanium tube filled with stacked graphite fins that were bonded in place by means of active metal brazing. This article describes the vacuum process and the methods used to evaluate the brazed titanium-graphite joints.

Because alloy steel hardenability is such an important factor in part manufacturing, the Center for Heat Treating Excellence (CHTE) is conducting research through simulations and laboratory testing aimed at learning more about the performance of gas quenching systems used to harden newer alloy steels. The primary goal of the study is to establish a standard method to evaluate gas-quench steel hardenability. Heat transfer coefficients will be determined for different gas pressures and during the cooling phase.

Flow measurement is an increasingly important part of quality control systems in the heat treating industry. This article covers selection basics, sizing, mass flowmeter overview, and frequently asked questions about about flowmeters.

In this article, the authors demonstrate the use of simulation software to optimize low-pressure carburizing (LPC) processes for high-alloy steels with strong carbide-forming elements.

The Center for Heat Treating Excellence (CHTE) was founded with the goal of bringing the industrial sector and university researchers together to find solutions to real-world problems. The Center, located at Worcester Polytechnic Institute (WPI) in Massachusetts, has 19 members from all areas of industry working together with WPI researchers to improve both heat treat and thermal processing methods worldwide. This article describes some of the current CHTE research projects.

There is growing interest in steels microalloyed with titanium, niobium, and molybdenum for use in high-temperature carburizing applications. This article describes methods for control of grain coarsening and work to commercialize microalloyed coarsening-resistant steels.