What is the difference between hot rolled and cold rolled steel?

Hot rolled is rolled above its recrystallisation temperature: softer, more ductile and cheaper, with a scaled surface and looser dimensional control. Cold rolled is rolled at room temperature: cleaner, with tighter thickness tolerance and higher strength but less ductility.

No. Aluminum contains no significant iron, so it is non-ferrous, which is why it does not rust and is non-magnetic. Copper, brass and bronze are non-ferrous too.

What is the difference between ferrous and non-ferrous metals?

Ferrous metals have iron as their principal constituent: carbon steel, stainless steel, cast iron. Non-ferrous metals do not: aluminum, copper, brass, bronze, zinc, titanium and magnesium. Ferrous metals are generally magnetic and rust unless alloyed or coated.

What are the most common sheet metal grades?

Carbon steel: Q235, DC01, SPCC, ASTM A1008. Stainless: 304 and 316. Aluminum: 3003, 5052, 6061. Together these cover most fabricated parts.

A36 or 1018 — which should I specify?

A36 for structural parts that will be welded: economical, widely available and easy to weld. 1018 for machined details needing a cleaner surface and closer size, such as shafts, pins and spacers.

What is 4130 chromoly used for?

High-strength structural and tubular parts where strength-to-weight ratio matters, such as motorsport, aerospace and bicycle frames. The chromium-molybdenum additions raise strength well above mild steel, at the cost of a demanding weld procedure and more springback.

What is the difference between 304 and 316 stainless steel?

316 adds molybdenum, resisting pitting from chlorides — ideal for marine and chemical duty. 304 is adequate and cheaper for indoor, food and general industrial use.

Is galvanized steel stainless steel?

No. Galvanized steel is carbon steel with a sacrificial zinc coating, while stainless resists corrosion through its own chromium content.

Does the grade change fabrication cost?

Yes. Harder grades cut slower, high-strength grades spring back, and alloy changes welding and finishing, so over-specifying can raise fabrication cost more than material price.