The flame hardening process is a cost-effective heat treatment technique. Primarily, it’s the high-intensity oxy-gas flame that keeps project expenditure low. The flame hardens localised workpiece areas, so application economy exists right there. Next, the movable flame head controls hardening depth, which is yet another cost-saving benefit. Now that we’ve begun investigating, the budget-centric benefits are coming thick and fast, with that mobile flame head really burning away the costs.

Cost Friendly by Design

There are engineering issues to solve here and logistical problems that ride alongside those mechanical puzzles. Flame hardening technology provides an immediate solution for the practical problems and those abstract but still very real monetary concerns. Basically, that single focused flame holds enough hardening sway to heat treat parts that are much larger than that lone tool. Known collectively as “Progressive Flame Hardening,” this wide surface area process variant moves like the beam on an old television set. It “scans” along the steel sheets or large cross-sectional area of a steel component to uniformly harden big areas, material segments that would otherwise require large amounts of widely distributed thermal energy.

The Ubiquitous Heat Treatment Solution

In an age where large industries create entire cityscape-like silhouettes, steel parts have scaled to meet demand. Post-processing technology emulates that scalability by using huge amounts of heat to harden unwieldy parts. Conversely, the scanning process we just outlined does the same job at a fraction of the cost. The flame head carries out its voyage across the part one line at a time. If the workpiece is a cylinder, then the flame head mounts on a spinning armature, one that spirals down the length of the cylindrical steel segment until it’s fully hardened.

A Perfect Match for Targeted Applications

The focused oxy-gas tool is also designed to work selectively. Remember, the outer teeth on a helical gearing assembly will require depth hardening, which works out well since this white-hot flame is quite capable of transmitting enough energy to case harden a set of gear teeth down as far as 10-mm. Similarly, the cost-effective flame hardens load-critical areas and intersections on steel frames and while leaving non-loaded sections malleable. Again, the result is an economical operation that nonetheless satisfies the project specs.

A single scanning torch is inexpensive to run. The head requires maintenance, and a fuel source needs to be reloaded occasionally. The spinning machine variant costs more, probably because multiple flame hardening heads work in tandem around that long cylinder. In conclusion, however, this affordable hardening solution is versatile. It accommodates complex geometries, larger workpieces, and is controllable, so depth hardened process consistency is as addressable as any uniform coverage strategy.

Processing variables are confounded when different alloys enter a heat treatment facility. Cooling temperatures and time periods adjust accordingly to metallurgical variances. Likewise, a worked hardened metal part is subjected to ingrained stress. The plastic deformation stress is removed by heat treating the part and making it workable again. These examples apply to steel, but non-ferrous metal treatment work emulates this standard iron-heavy processing configuration, although there are differences between the two metal families.

Cold Worked Parallelism 

Non-ferrous metals use the same cold work techniques as ferrous products. Copper is bent in the workshop, then aluminium and zinc are sheared. They’re drawn and compressed just like a similarly profiled steel workpiece. Naturally, the metals we just mentioned are more ductile than iron, plus they’re characterised by different transformative temperatures, so the heat treatment work envelope has to adapt to these processing changes, but that cold working layout is relatively indistinguishable from the ferrous-sourced setup. However, there are always exceptions to any rule, and such is the case here, for some non-ferrous metals are not cold workable. Certain copper alloys, for example, resist cold workshop tooling methods.

Non-Ferrous Metal Heat Treatment 

Although it’s true that these metallurgical groups are amazingly versatile, that versatility factor can hamper the heat treatment process. Essentially, iron-free metals don’t react as predictably as steel when they’re hardened or otherwise mechanically altered. They do subscribe to the annealing process, though, so a strain-hardened component can be softened by heat-releasing the grain’s internal stresses. Otherwise, using aluminium as an example here, a ferrous-centric hardening and quenching cycle is simply not an option. Instead, we call upon the services of a precipitation hardening process. It’s here that lower furnace temperatures age the alloys until precipitates are formed. Quenching does follow the hardening work, just like it does in a ferrous-oriented workshop, but this is a water quenching station, not an oil bath.

As proven by these changed processing variables, a non-ferrous metal heat treatment setup deploys its equipment in a different manner. There are temperature and time variables to account for, such as magnesium’s 300-320°C annealing temperature, then there’s the kinetics, the operability changes to incorporate into the process. Non-ferrous hardening technology takes a sharp turn into a contrasting methodology, a place where precipitation hardening and water quenching take charge. On top of this realisation, many grades and alloy forms sub-branch from the non-ferrous metal groups, and these groups require cold work (cold rolling) technology to accommodate their unique hardening requirements.