Stainless steel does not "rust" as we commonly think of it, with red oxide flakes that peel off. It holds up very well against the hot water in your dishwasher, but it's the other stuff in your dishwasher that can cause these orange spots.
Too much detergent
Most detergents contain chlorides, which should be avoided, but nearly all of the detergents sold in stores contain them. You can reduce the problem by not using too much of it.
The dishwasher isn't a sterile environment; it's quite a dirty one, with a variety of mineral deposits that can include calcium, magnesium, iron, aluminum, and manganese. In the high temperatures of the dishwasher, these particles can react with the steel. If you see the orange spots, it's probably due to iron particles that have contaminated the surface of the stainless steel, and the particles are rusting (not the steel).
Caring for you cutlery can help keep it looking pristine and shiny for many years of use. It is important to always follow the manufacturer's suggestions for use and maintenance. Otherwise, even stainless can pit, corrode and discolor. Follow these tip and 5 easy steps for caring for your flatware.
1. Do not allow food to sit on your flatware for a long period of time
Rinse all food and residue off your flatware immediately after use. Some foods are very harsh to the stainless and can cause pitting, erosion and discoloration. These foods include: Tea, Coffee, Vinegar, Salt, Mustard, Mayonnaise, and Eggs.
2. Pre-soak your flatware before washing
Soak your flatware in a plastic or stainless steel container for up to 10 minutes. Do not soak for long periods of time or overnight, as this can cause corrosion. Avoid soaking in or with aluminum or copper materials. Use a chlorine-free solution for all setps of cleaing.
3. Washing your flatware
When using a dishwasher, load forks and spoons handle down. Place knives in a separate basket with the blade down to prevent scratching and contact with other metals. Do not load with other types of metal. Use a minimal amount of detergent. Avoid detergents with citrus (lemon and orange). Remove flatware from the dishwasher after the last rinse. Do not allow your flatware to go through the dishwashers dry cycle.
When hand washing, use hot water and mild soap. Do not use metal scrub brushes or scrapers, as this can cause abrasion and increase corrosion and discoloration. Rinse thouroghly.
4. Drying your flatware
Hand dry immediately with a soft cloth and store.
Periodically, you may want to use a high quality stainless polish to remove any discoloration or stubborn spots. Rinse thouroghly.