When a surgeon places an implant into a patient, it is a moment of profound trust. Whether it is a Titanium hip replacement, a spinal rod, or a delicate surgical drill bit, the material must do more than just hold weight or cut bone—it must essentially become invisible to the body's immune system.
This seamless integration, known as biocompatibility, is not solely determined by the alloy selected. It is unlocked through the precise, controlled science of heat treatment.
At Rex Heat Treat, we understand that the difference between a successful implant and a rejected one often comes down to what happens inside the furnace. For over 80 years, we have refined our medical device heat treating service to ensure that lifesaving tools perform flawlessly in the most demanding environment on earth: the human body.
Biocompatibility is often misunderstood as a simple material property, like composition, weight, or density. In reality, it is a dynamic relationship between the surface of the device and the living tissue surrounding it. When a foreign object enters the body, the immune system immediately investigates the surface energy and chemistry of the invader
If the surface is chemically unstable or carries residual contaminants from machining, the body may attack it, leading to inflammation or encapsulation (where the body walls off the device with scar tissue). Optimized heat treating alters the microstructure of the metal to encourage "osseointegration"—the direct structural and functional connection between living bone and the surface of a load-carrying implant.
Most medical-grade alloys that require heat treatment are high-strength stainless steels, high-speed tool steels, specialty Titanium alloys, Inconels, and other specialty metals. In all cases, these metals require a high temperature cycle, rapid cooling, and then a lower temperature cycle to reduce stresses and/or guarantee mechanical strength, ductility, and toughness requirements.
This is where Rex Heat Treat’s specialized capabilities come into play. For long, slender medical components like intramedullary rods or surgical drills, heat treating will cause distortion.
We utilize our proprietary vertical gantry and vertical vacuum furnaces to process these parts. By suspending long parts vertically, we allow gravity to work for us rather than against us, ensuring the component remains perfectly straight while internal stresses are relieved.
This geometric stability is the first step in ensuring the body "accepts" the mechanical function of the device without irritation from misalignment.
Different medical applications require different thermal strategies. As a premier medical device heat treating service, Rex Heat Treat customizes the process for the specific alloy in use. Below are some examples of Rex’s premier medical heat treat services.
Titanium (6Al4V, 6AL4V ELI, 15Mo): Titanium is the gold standard for implants, but it is highly reactive to oxygen and hydrogen at high temperatures. Most Titanium alloys require a high-temperature solution heat treat, fast water quench, and an age hardening cycle. Utilizing an experienced heat treater who understands and avoids the common failures of Titanium will save you money, time, and promote product confidence.
Stainless Steel (440 alloys, PH steels, and more): Used frequently in surgical instruments such as forceps and cutters, stainless steel requires a balance of hardness (to retain a sharp edge) and corrosion resistance (to withstand repeated sterilization). Our solution heat treatment and precipitation hardening processes are designed to maximize this balance, ensuring instruments remain rust-free and sharp through hundreds of autoclave cycles.
In the aerospace and nuclear industries, a part failure is catastrophic. The medical industry is no different, but the variables are biological. A heat treat process that leaves behind even a microscopic amount of carbides, non-martensitic transformation products, or decarburization can compromise the integrity of a device or implant.
Rex Heat Treat’s facility in Lansdale is equipped with rigorous quality controls to meet these standards. Our NADCAP accreditation and integrated metallurgical labs allow us to verify that every batch meets the strict microstructural standards required for medical use. We don't just heat treat metal; we document, verify, and certify it.
Whether you are prototyping a new spinal implant, hospital bed struts, or scaling production on surgical drill bits, Rex Heat Treat has the vertical capacity and metallurgical expertise to help you succeed.
Contact us today to learn how our optimized processes can enhance the performance and acceptance of your medical materials.