④ FAQ/技术文章
Hot Rolled vs Normalized Steel Plate
Buyers meet these two words on every quotation, yet they describe different things: hot rolled is a rolling condition, normalized is a heat treatment. This page explains what each means for a plate like Q355B (GB/T 1591) and how to decide which one to order.
Short AnswerHot-rolled plate leaves the mill and cools in air with no further treatment — it is the as-rolled condition. Normalized plate is reheated above its transformation range and cooled in air again, refining the grain and making properties more uniform across the whole plate. For a drawing that just says "structural plate", as-rolled Q355B is usually what you get. When the drawing calls for normalized delivery, it is asking for that extra uniformity and guaranteed toughness — and the actual condition of your order is always stated on the mill test certificate.
What Each Condition DoesRolling shapes the plate at high temperature; as-rolled material simply cools from that state. It is economical and entirely adequate for most static structures. Normalizing re-austenitizes the plate and air-cools it: grains re-form finer, and the property spread between surface and center, edge and middle, shrinks. That is why drawings for welded, impact-loaded or low-temperature service often specify normalized or controlled-rolled delivery. Neither treatment changes the grade chemistry — a normalized Q355B plate still carries the same GB/T 1591 composition and the same strength anchors: 355 MPa minimum yield up to 16 mm and 470–630 MPa tensile.
How to ChooseOrder as-rolled when the structure is statically loaded, the plate is moderate in thickness, and no special toughness is specified — it is the fastest and most economical route. Choose normalized when the joint is welded through substantial thickness, the service temperature drops (pair the condition with Q355C/D/E, whose 34 J impact is specified at 0, −20 or −40 °C), or the designer explicitly requires uniform properties through the plate. When in doubt, send the drawing: the delivery condition is a line item we confirm with the quotation, not a guess.
What It Means for Price and Lead TimeNormalizing is an extra furnace step after rolling, so a normalized plate typically prices above its as-rolled twin and can add some lead time, depending on mill schedules. Stock plates ready to ship are commonly as-rolled; if your project needs normalized delivery, we quote the as-rolled and normalized options side by side so you can weigh the extra cost against the design requirement — no obligation to take the dearer route unless the drawing demands it.
Quick ReferenceAs-rolled = shaped at the mill, cooled in air, condition shown on the MTC; normalized = reheated, air-cooled, finer grain, more uniform through-thickness properties. Same grade chemistry either way — the letter after Q355 (B/C/D/E) sets the impact requirement at +20, 0, −20 or −40 °C with 34 J minimum. The deciding documents are your drawing and the mill test certificate: the first says what to order, the second proves what arrived.