Compare Metals & Grades

SS 304 and SS 316 are the two most widely used austenitic stainless steel grades in India. The key difference is molybdenum: SS 316 contains 2–3% Mo, which dramatically improves corrosion resistance against chlorides, seawater, and many acids. SS 304 is cheaper, easier to source, and adequate for most general-purpose applications.

SS 304L is the low-carbon version of SS 304 — the "L" stands for "low carbon" (max 0.03% vs 0.08% in standard 304). The lower carbon prevents carbide precipitation during welding, which would otherwise cause intergranular corrosion in the heat-affected zone.

SS 316L is the low-carbon version of SS 316. Both contain molybdenum for chloride resistance, but 316L (max 0.03% C) avoids carbide precipitation during welding, making it the standard choice for welded marine and chemical fabrications.

SS 202 substitutes most of the nickel in 304 with manganese and nitrogen, making it 20–30% cheaper. It looks identical to 304 but corrodes faster, especially in humid or salty conditions. It is widely used in low-cost kitchen utensils and decorative work.

6061 and 6063 are both heat-treatable Al-Mg-Si alloys but designed for different purposes. 6061 has higher strength and is the structural workhorse. 6063 has lower strength but excellent surface finish and extrudability — the standard for architectural sections like window frames.

Mild steel (low-carbon steel) and stainless steel are two completely different families. MS is cheaper and stronger per rupee but rusts. SS contains chromium that forms a protective oxide layer, making it corrosion-resistant — but at 4–8× the price.

Mild steel is technically a sub-category of carbon steel — specifically low-carbon steel (≤ 0.25% C). "Carbon steel" as a term usually refers to medium and high-carbon grades that are harder, stronger, and less ductile.

Tool steels are designed for cutting, forming, and shaping other materials — they prioritise hardness and wear resistance. Spring steels are designed to repeatedly flex without permanent deformation — they prioritise high yield strength and fatigue life.

Brass is copper + zinc. Bronze is copper + tin (and sometimes aluminium, silicon, or nickel). Both are decorative, corrosion-resistant copper alloys but they differ in colour, hardness, and behaviour in marine environments.

Pure copper has the highest electrical and thermal conductivity of any common metal. Brass — copper alloyed with zinc — sacrifices some conductivity for much better machinability, hardness, and cost-effectiveness.

Hot rolling and cold rolling are manufacturing processes, not grades. Hot-rolled (HR) steel is rolled above its recrystallisation temperature (~1000°C) — cheap and strong but with a rough scale finish and looser tolerances. Cold-rolled (CR) steel is further processed at room temperature — better finish, tighter tolerances, higher strength.

Seamless pipe is extruded from a solid billet — no weld seam, uniform strength all around. ERW pipe is rolled from a flat strip and welded longitudinally with an electric resistance weld. Seamless is stronger and more reliable for high-pressure or critical service; ERW is cheaper and more readily available in larger sizes.