For cost-effective yet corrosion-resistant automotive parts, car parts supplier would recommend the following materials:
Stainless steel
Stainless steel alloys like 304 or 316 steel are moderately priced, corrosion resistant and durable. They can work well for things like shafts, housings, brackets, bolts, etc. While not the cheapest option, stainless steel provides good value for the properties it offers.
Aluminum with anodizing
Aluminum is lightweight, inexpensive and corrosion resistant when anodized. Anodizing forms an oxide layer that helps protect the aluminum. It works great for components like wheels, frames, body panels, etc. The anodizing process does add to the cost, but still keeps it relatively affordable.
Corrosion-resistant coatings
Coatings like zinc plating, chromating, or corrosion-resistant paint/powder coating can be applied to mild steel or other alloys to provide corrosion protection at a lower base cost. These coatings extend the life of the part while still controlling expenses. They work well for high-volume production parts.
Corrosion-inhibiting additives
For components made of low-cost steel, adding corrosion-inhibiting chemicals or compounds during manufacturing can help prevent rust and corrosion. Molybdenum disulfide is one example of an additive that is relatively inexpensive and easy to incorporate into steel. It does increase the cost slightly but not dramatically.
Magnesium alloys
For high-strength to weight ratio parts, magnesium alloys provide an excellent combination of properties and value. Magnesium is lightweight, affordable and corrosion resistant, especially when coated or alloyed. Higher strength alloys do cost a bit more but are still often very budget-friendly for their performance. Magnesium would work for components like steering knuckles, brake calipers, crankcases, etc.
Plastics and composites
For some parts, high-performance plastics and fiber-reinforced composites can achieve corrosion resistance and low cost. Polymers like glass-filled nylon, PTFE, PEI and polypropylene have good corrosion resistance and low cost. Fiber composites include carbon fiber, Kevlar or glass fiber reinforcement. These materials excel for complex shapes, tapings, gaskets, sealing rings and other non-structural parts.