Water Jet Cutting Advantages? Among the Many. . .No Heat. . . No Heat Affected Zone!
No Heat affected Zone (HAZ) . . . I would say that among the many, many advantages to Wet Jet Precision's water jet cutting over other metal cutting tools, this is a huge plus.
Cutting operations involving extreme temperatures, such as oxyfuel and plasma arc Metal Cutting Equipment, create thermal problems on the edge associated with the cut that cause microstructural and metallurgical alterations within the metal.
The area of any metal work-piece which has been thus affected by heat is termed the “heat affected zone” or HAZ. All thermal cutting methods produce an HAZ within the cut metal.
Depending on the material being cut, the heat affected zone caused by most other cutting models produces physical changes at the cut edge.
The transformations caused as a result of heat can include:
Changes associated with the microstructure of specific steels, resulting in an increase in the hardness to the cut edge in comparison to the un-cut metal.
Changes associated with the microstructure of specific steels, resulting in a decrease in the strength of the cut edge.
The development of nitrides at the cut edge that may affect its weldability.
Darkening, discoloration, or heat tinting of the surface area of the metal alongside the cut edge.
Distortion to the metal getting cut.
A few transformations, for example heat-tint, are aesthetic and don't make any difference in certain usages. With some other uses, heat tinting could be critical.
The size of the heat-tint depends on the particular surface state of the metal. Any kind of surface contaminant or finish, like paint, oxidation, or oil is going to have an effect on the formation of heat-tint.
HAZ width is determined solely from the thermal past of the metal. Although coloration of the metal may be about the same width as the heat affected zone, heat-tint width is often either greater or smaller than the HAZ.
Keep in mind that the HAZ is within the metal so you can't see it. Do not suppose that it is the same width as the discoloration, or tinting. Maybe, but probably not.
Additional transformations to the metal, such as warping or hardening, have an effect on weldability. The HAZ might need to be somewhat or entirely taken off by grinding before the metal part can be utilized.
The width of the heat affected zone is generally determined by the speed of the cut. Faster speeds will typically result in a smaller HAZ.
The properties of the metal being cut also determine the HAZ. Every metal conducts heat and reacts differently to high temperatures. Generally, the longer the metal is subject to the heat, the wider the HAZ.
One other thing to be aware of concerning the HAZ is that when cutting thicker metals the width of the heat affected zone could be smaller at the top of the cut edge and bigger at the bottom.
In summary, the Heat Affected Zone is responsible for stressing or deforming and discoloring the metal, and hardening or annealing the cut edges. Heat expands the metal, and as it cools, it contracts altering the very molecular structure of the steel.
Again, depending on the material, this can create big problems that require secondary processes.
Kind of like us humanoids when we have to take the heat, sometimes it creates problems!
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