Heat Treatment of Firearms-“Blaser” Part II
Yesterday “The Monty” posted Part I of a two-part article entitled “Heat Treatment of Firearms-“Blaser”. In this article we look at the manufacturing process and subsequent heat treatment of firearms produced by “Blaser” of Isny, Germany.
While the firm makes virtually all of the components for their line of high end rifles and shotguns heat treatment is reserved almost entirely to the gun barrels themselves. The brief summary (with the help of Mr. AI) is that “Blaser” treats the barrels using a sequence of pre-hardened material selection, cold-hammer forging, and specialized plasma nitriding alongside Diamond-Like Carbon (DLC) surface technologies. Unlike manufacturers who heat treat raw steel blanks after the barrel is formed, Blaser avoids traditional post-forging heat treatment on the complete barrel profile. Subjecting a finished barrel to extreme hardening temperatures can warp and bend the precise alignment of the bore.
The company starts with long circular bars of steel which arrive at the plant already hardened and tempered. The solid bars are then cut, drilled, and reamed. The drilled blank is then processed in a cold-hammer forging machine. Four timed hammers forge the steel over a precision mandrel at room temperature (under 20°C). This compresses and stretches the metal to shape the rifling and the chamber simultaneously. Because this is done cold, it preserves the steel molecular structure and avoids introducing heat-induced straightness errors.
For some of the firm’s products, induction hardening is used to heat treat the locking lug region-this is a process outsourced to a local commercial heat treater.
The heart of the heat-treating process is Plasma (Ion) nitriding which takes place in a dual retort plasma nitriding system provided by “Rubig” of Austria. Subsequent to this the barrels receive a DLC (Diamond-Like Carbon) finish which again takes place in a system provided by “Rubig”. The DLC system provides corrosion resistance, a highly scratch-resistant finish, as well as giving the barrels their very distinctive black color. While our knowledge of “DLC” is limited, we did learn from “Mr. George Immler”, (Heat Treat and Surface Treatment Manager) that settings for the process are entirely dependent upon the total surface area of the parts, meaning a successful result relies upon knowing the exact size and weight of the total load.
Various other manufacturing processes included Laser Engraving which can add up to 20 hours in production time, high end vacuum part cleaning provided by “HEMO” of Germany, shot peening and sand blasting.
Not every gun manufacturer uses the same heat treatment technology. “The Monty” can attest to the fact that gun manufacturers in North America use a number of different heat treat options although gun manufacturer Glock in Smyrna, Georgia also uses plasma nitriding along with gas nitriding and carburizing in their heat treat department. In the case of “Blaser” they consider plasma nitriding a tried and true process that has provided the company with a top notch product. We would not argue with them.
