Answers to the questions steel buyers ask most often about coil, pipe, rebar, structural sections, stainless sheet and pricing. Each answer comes from the technical guides on this site; follow the links at the end of each section for the full article. Prices are reference ranges and every final quotation is confirmed against your grade, size, quantity and delivery terms.
Zinc and aluminium-zinc coating classes, PPGI and PPGL paint systems, certificates and everyday GI coil issues.
A: No. AZ150 is an EN-style designation meaning roughly 150 g/m² total coating mass on both surfaces. AZ50 is an ASTM-style designation in oz/ft², and 0.50 oz/ft² works out at approximately the same 150 g/m². They describe comparable coating masses in different units.
A: 0.21–0.50 mm on the current product listing, in grade S350GD with AZ150 coating. Requirements outside that band fall under custom production and should be raised in the enquiry.
A: It should not. Specify base metal thickness explicitly and require the MTC to report it that way, because suppliers reporting total coated thickness will appear cheaper on the same nominal number.
A: Galvalume generally performs better in open atmospheric exposure, galvanized generally protects cut and sheared edges better. Highly cut or perforated components in salt-laden air often favour galvanized; large uncut roofing panels favour galvalume.
A: Luyuan supplies a full English Mill Test Certificate with shipments covering chemical composition and mechanical properties. Company-level certifications include ISO 9001, ISO 14001, ISO 45001 and RoHS. SKU-level coating certificate numbers are not published publicly and should be requested directly against a specific order.
A: Not published at product level. Request it alongside your specification, since MOQ interacts with width and coating class on a customised run.
A: No. PPGL generally performs better in open atmospheric exposure and hot climates. PPGI generally protects cut and sheared edges better and tolerates contact with alkaline materials such as wet mortar. Heavily punched or perforated components often favour PPGI.
A: 0.21–0.50 mm on the current product listing, in DX51D. Requirements outside that range fall under custom production and should be raised in the enquiry alongside width and coating class.
A: Specify base metal thickness explicitly and require the MTC to report it that way. A supplier quoting total thickness including metallic coating and paint film will appear cheaper at the same nominal number.
A: Colour retention over years of UV exposure, and price. PE is the entry system; PVDF holds colour longest and costs the most. SMP and HDP sit between them. The choice should follow the project's exposure and warranty requirement, not the sample card.
A: Custom RAL colours, paint types and coating weights are supported at service level. Agree gloss level, colour tolerance and a signed reference sample before production, since batch-to-batch colour matching cannot be corrected after shipment.
A: A full English Mill Test Certificate is supplied with shipments. Company-level certifications include ISO 9001, ISO 14001, ISO 45001 and RoHS. SKU-level certificate numbers are not published publicly and should be requested against a specific order.
A: In most trade usage, yes, with one distinction: GP specifically means the plain, uncorrugated form, while GI is the broader term for zinc-coated steel in any form. Neither abbreviation specifies grade, coating mass or thickness.
A: GC is corrugated, produced by roll-forming a flat galvanized sheet into a profile. GP is the flat material before that step. Buyers purchasing GP are usually buying input for their own forming line.
A: Z120 on the current product listing, in DX51D or SGCC, at 0.18–0.30 mm. Application pages elsewhere reference zinc coatings up to Z275, which should be confirmed against a specific order rather than assumed.
A: No. Z275 refers to zinc coating mass of approximately 275 g/m² across both surfaces, not to steel thickness. Base metal thickness and coating mass are two independent parameters and both belong in the specification.
A: That is most likely white rust from trapped moisture during transit or storage, not a coating defect. Passivation, moisture-barrier packing and covered ventilated storage on arrival are the controls. Specify all three in the contract.
A: A full English Mill Test Certificate is supplied with shipments. Company-level certifications include ISO 9001, ISO 14001, ISO 45001 and RoHS, obtained in 2018. SKU-level certificate numbers are not published publicly and should be requested against a specific order.
A: No. It is more corrosion resistant per unit area because it carries more zinc, which makes it the correct choice outdoors. For a painted indoor part where surface uniformity and dimensional consistency matter more than sacrificial life, electro-galvanized material performs the job at lower coating cost. "Better" only has meaning once the service environment is defined.
A: Z120 designates 120 g/m² of zinc, total across both surfaces. Since zinc has a density near 7.1 g/cm³, 120 g/m² total corresponds to roughly 8–9 µm per side as a nominal average. Use the g/m² figure in contracts and the micron figure for inspection discussion, not the reverse.
A: EN 10152 defines electrolytic zinc coated flat products on a cold rolled base, so under that standard the answer is no. If a supplier offers "hot rolled electro-galvanized coil," ask which standard and which mill, and expect the specification to be non-standard.
A: For most construction and general fabrication supply, yes, subject to the Mill Test Certificate showing the actual tested properties. For deep drawing or any application where elongation is a controlled parameter, treat the two as different and check the certificate values against your requirement, because the minimum requirements in the two standards do not align.
A: It can. Heavier hot dip coatings have thicker zinc-iron intermetallic layers, which are harder and more brittle than free zinc, so very heavy classes can powder or flake at tight bend radii. If you are roll forming a tight profile at Z275 or above, ask for the mill's bend-test data for that coating class and gauge rather than assuming it behaves like the Z100 you formed last year.
A: A Mill Test Certificate in English, traceable to the heat number, showing chemical composition, mechanical properties and coating mass; packing list with coil numbers and weights; and the inspection report if third-party inspection was agreed. Luyuan supplies English MTCs with shipments and accepts SGS, BV, Intertek or buyer-appointed inspection.
A: Aluminium-zinc coated product (AZ designation) generally offers longer atmospheric life per unit coating mass in chloride-bearing environments, while zinc offers better cut-edge protection and better behaviour under painting in some systems. Once your environment analysis pushes you past Z275, price both routes rather than escalating the Z class by default.
Read more: Galvalume Sheet Specs: Thickness, AZ Coating and Grades | PPGI Sheet Guide: Coatings, Thickness and PPGL Options | What Is a GP Sheet? Galvanized Plain Sheet Specs and Uses | Hot Dip Galvanized Steel Coil vs Electro-Galvanized Coil
Grades, thickness ranges, annealing, mill scale and when to choose hot rolled or cold rolled.
A: They're close but not identical. Q235B has a 235 MPa minimum yield strength under GB/T 700; A36 specifies roughly 250 MPa (36 ksi). They're commonly cross-referenced but remain separate specifications — order to the standard named on the project drawing.
A: 2–10 mm, with ±1% tolerance. Thinner material in coil form is available separately at 0.12–4.0 mm under the HR Coil line.
A: Yes, hot rolling leaves a mill-scale surface. If the material is going straight to welding, painting, or coating, factor in a pickling, blasting, or grinding step before that process.
A: Yes — name the specific standard on the purchase order and confirm it's reflected on the Mill Test Certificate, rather than relying on a general grade-equivalence note.
A: All three are JIS G3141 cold-rolled carbon steel grades. SPCC is commercial quality for bending and shallow drawing, SPCD is drawing quality for moderate deep-drawing, and SPCE is deep-drawing quality with the lowest carbon content for the most demanding forming operations.
A: 508 mm and 610 mm. Confirm which one matches your decoiling equipment before ordering — the two aren't interchangeable on most uncoilers.
A: 0.12–5.0 mm in coil form. Cut sheet is available separately at 0.20–0.50 mm.
A: Cold rolling work-hardens the steel, reducing ductility. Annealing restores formability before the material goes to a press or roll-former. Black annealing and bright annealing produce different surface appearances.
A: Reference pricing is roughly USD 585–635 per metric ton, though final pricing depends on grade, thickness, coil ID, annealing, and order volume.
A: Hot rolled material generally sits below cold rolled per tonne because it skips the cold reduction and annealing steps. Luyuan does not publish a listing range for hot rolled products, so the comparison should be made on two live quotations rather than on published figures.
Read more: Hot Rolled Steel Sheet: Grades, Thickness and Tolerances | Cold Rolled Steel Coil: Grades, Thickness and Coil ID
NPS and DN, real outside diameters, Schedule 40 and 80, coating standards and documents.
A: 60.3 mm, equivalent to 2.375 inches, under both ASME B36.10M and EN 10255. DN50 is the metric label for the same pipe. The 2 inch figure describes neither the outside diameter nor the bore.
A: They are the same nominal size, but the outside diameter depends on the standard: 33.4 mm under ASME/ASTM and 33.7 mm under EN 10255/ISO 65. The 0.3 mm difference is normally absorbed by threading tolerance. At DN65 and DN150 the equivalent difference exceeds 3 mm and is not absorbable.
A: For DN80 the SCH 40 wall is 5.49 mm and SCH 80 is 7.62 mm; under EN 10255 medium series it is 4.05 mm and heavy series 4.85 mm. Schedule is not a thickness, so the answer only exists once the size is fixed.
A: No. Coating thickness is measured and specified separately, and it is added to the outside diameter rather than to the steel wall. Structural and pressure calculations use the steel wall only.
A: Pre-galvanized pipe is roll-formed from already-coated strip, leaving the weld seam and cut ends bare. Hot-dip galvanized pipe is coated after welding, so the seam, the bore and the ends receive zinc. Pre-galvanized costs less and suits dry indoor or short-service applications; hot-dip is the choice for buried, humid or outdoor exposure.
A: Either works, but state which governs. Per-tonne pricing with theoretical weight is the export norm; per-metre requirements should be converted using W = (OD − WT) × WT × 0.02466 before comparing quotations, because two pipes of the same DN can differ by 6% or more in weight per metre.
A: Yes, and it usually is. Threads cut after galvanizing expose bare steel, so the applicable standard requires the exposed thread to be protected. Confirm at the enquiry stage what protection the mill applies, because practice varies.
A: Most sizes can be produced at 12 m, but the constraint is usually shipping rather than production. A 12 m bundle needs a 40 ft container or flat rack, and the fit is tight enough that 11.8 m is often supplied instead. Confirm the exact cut length before the container is booked.
A: They're the same size classification system expressed in two units — NPS in inches (common in North America and English-language specs), DN in millimeters (common in European and international documentation). NPS 2 equals DN50.
A: Neither — both share the same OD within a given NPS/DN size. Schedule 80 has a thicker wall and smaller inside diameter than Schedule 40 at the same nominal size.
A: NPS 1 / DN25 has an actual outside diameter of 33.4 mm, with a Schedule 40 wall thickness of 3.38 mm.
A: No. SHS/RHS square and rectangular tube is sized by cross-section dimension in millimeters (e.g., 50×50 mm) plus wall thickness, not by NPS or DN — the two systems aren't interchangeable.
A: This depends on your project spec; hot-dip galvanizing is commonly referenced against ASTM A123. Confirm the specific coating weight and standard with your supplier in writing, since it's not always implied by the word "galvanized" alone.
A: Both. Seamless pipe is available under ASTM A106, ASTM A53, or API 5L with OD 10–700 mm; welded pipe is available in Q235B/Q355B grades via ERW or EFW in standard 6 m lengths.
A: Luyuan's reference range is approximately USD 608–623 per metric ton, varying with grade, schedule, coating, and volume — confirm current pricing and coating specification at RFQ stage.
A: An English Mill Test Certificate at minimum, plus third-party inspection (SGS, BV, Intertek, or buyer-appointed) on request before shipment.
Read more: Galvanized Steel Pipe Sizes: NPS, DN and Wall Thickness | Galvanized Steel Pipe Sizes: NPS, DN, OD Chart and Schedules
HRB400 and HRB500 versus ASTM grades, welding, coil rebar, test certificates and pricing basis.
A: In normal usage, yes. Rebar is short for reinforcing bar, and nearly all reinforcing bar sold for structural use today is deformed. The term "deformed bar" specifies the surface condition explicitly; "rebar" specifies the function. A supplier who offers you "rebar" is almost certainly offering deformed bar, but if the application is bond-critical, write "deformed" into the enquiry and let the packing list confirm it.
A: No. Grade 60 is 60,000 psi, roughly 420 MPa, which lines up with HRB400. HRB500 is a 500 MPa minimum yield bar and sits above Grade 60. Substituting in either direction changes the structural basis of the design and needs the engineer's written approval.
A: It designates the seismic grade, carrying additional ductility requirements including a tensile-to-yield ratio and elongation criteria beyond the base grade. Projects in seismic zones normally specify the E grade, and the mill certificate must report those values.
A: Only with a qualified procedure and confirmation of the carbon equivalent from the certificate. Higher-strength carbon rebar is more sensitive to welding heat, and the base specification for plain carbon rebar generally does not guarantee weldability. If welding is part of the method statement, say so at enquiry so that a weldable specification is quoted.
A: It is a length of deformed reinforcing bar welded to a steel embed plate and cast into concrete to anchor an attachment. The material you order is reinforcing bar in the specified grade and diameter; the anchor is created by fabrication. Do not substitute bar diameter or grade, because the anchor capacity calculation is tied to the specific bar the engineer assumed.
A: For light stirrups and ties in low-load applications, spacers, and non-structural uses where bond is not the controlling mechanism. Where plain bar carries load, end hooks or bends are normally required to make up for the absence of rib bearing.
A: Light surface rust that leaves the rib profile intact after wire brushing is generally acceptable and can marginally improve bond. Loose flaking scale that removes material and reduces the effective rib height is a legitimate reason to reject. The test is what the bar looks like after brushing, not what it looks like on the truck.
A: Heat number, chemical composition including carbon equivalent, yield strength, tensile strength, elongation and bend test results, against the named standard and grade. Check that the grade on the certificate matches the grade on your purchase order, including any seismic suffix, rather than only checking that the numbers look high enough.
A: Coil is a delivery form, not a grade. Small diameters are commonly supplied in coil for decoiling and cutting on site or in a rebar shop. The grade is whatever the order specifies. What does change is straightening: coil requires a decoiler and straightener, and the straightening process should not be allowed to damage the rib profile.
A: The published range is 5.5–16 mm. Larger diameters should be confirmed directly against current mill availability before they're added to a bid.
A: Yes — the published delivery formats are 6 m, 9 m, and 12 m cut lengths, or coil.
A: A full English Mill Test Certificate is included. SGS, Bureau Veritas, Intertek, or a buyer-appointed inspector can be arranged for third-party pre-shipment inspection on request.
A: Rebar isn't on Luyuan's current public reference price list, so pricing is quoted per order based on grade, diameter, length format, and volume.
Read more: Deformed Bar vs Rebar: Grades, Bond and Where Each Is Used | Deformed Steel Bars: Grades, Diameters and Standards
Wide flange versus H sections, substitution, columns, grades, lengths, tolerances and documents.
A: In common usage, yes. "Wide flange" is the American term for the parallel-flange section designated W; "H beam" is the term used in Chinese and Japanese practice, subdivided into HW, HM and HN by depth-to-width ratio. The European equivalents are the HEA, HEB and HEM series.
A: In small depths, taper-flange I-sections are often cheaper where they are locally stocked, because the mass per metre is lower. At larger sizes and for anything carrying axial load, the comparison should be made on delivered cost for the required capacity, not on price per metre. Luyuan's published reference range for H-beam steel is approximately USD 440–568 per metric ton, which is a listing indication rather than a quotation.
A: Not without checking. Same nominal depth does not mean same section modulus, same weight or same flange width. The substitution also changes the connection geometry, the bolt gauge lines and often the coating area. Run the checks, and get the substitution approved by the engineer of record.
A: Luyuan's published H Beam listing states 1,000–12,000 mm. Longer members are normally achieved by splicing, which needs to be designed rather than decided in the field.
A: HN identifies the narrow-flange H series. The numbers are nominal depth in millimetres by nominal flange width in millimetres. Web and flange thicknesses come from the dimensional table in the governing standard, which is why the standard has to be named alongside the designation.
A: A wide-flange section, in almost every case. Column capacity is limited by buckling about the weaker axis, and the near-square proportion of the HW, HEB or W series brings the two axes closer together. Narrow sections used as columns are inefficient at anything but very short heights.
A: It depends on the service temperature, the plate thickness and the design code the project is built under. Many European and Chinese grades carry subgrade letters that correspond to impact-test temperatures. If the specification names a subgrade, the testing requirement travels with it and should appear on the certificate.
A: The H Beam product listing publishes Q345. Other hot-rolled structural grades including Q235B, Q345B, A36, S235JR and S355JR appear on solution-level pages, which indicates application experience rather than a confirmed SKU. Send the required grade and standard in the RFQ so availability can be confirmed against actual rolling programmes.
A: Name the dimensional tolerance standard in the purchase order, then include dimensional verification in the pre-shipment inspection scope. Luyuan states that 100% pre-shipment inspection is carried out and that SGS, Bureau Veritas, Intertek or buyer-appointed inspectors are accepted, so the checks can be witnessed independently.
A: For strong-axis bending in a simple span, the two can perform similarly at comparable weight. The real gap is weak-axis stiffness, where H-beam's wider, parallel flange outperforms a tapered I-beam's narrower flange.
A: Sometimes, but connection detailing needs review first — base plates, clip angles, and bracing hardware sized for a tapered flange may not seat correctly on a parallel-flange H-beam without redetailing.
A: Not as a confirmed current catalog entry — treat it as a price-on-request item pending mill confirmation rather than an assumed stock product.
A: This isn't published on Luyuan's current listing and should be confirmed in writing before order placement, since tolerance class affects fit-up in bolted connections.
A: Luyuan's reference range for H-beam is approximately USD 440–568/MT, depending on section, grade, length, and volume — confirm current pricing and Incoterms at RFQ stage rather than relying on a published range as a final quote.
A: An English Mill Test Certificate at minimum, with third-party inspection (SGS, BV, Intertek, or a buyer-appointed inspector) available on request before shipment.
Read more: H Beam vs I Beam: Choosing Sections for Structural Work | H Beam vs I Beam: Comparison Table and 5-Step Selection Guide
ASTM A240 304 and 304L, finishes, plate versus sheet and what the mill test certificate should show.
A: They describe closely related material but they are not the same kind of document. AISI 304 is a grade designation from a numbering system that is no longer maintained for new grades. ASTM A240 is a current product specification with defined chemical limits, mechanical minima and testing requirements, and its Type 304 limits are not identical to the legacy AISI figures still quoted on many datasheets. Buy to A240 and cite the edition.
A: Not as a substitution decision you make yourself. Code construction requires material to the SA specification, in this case SA-240, with the documentation the Code requires. Ask for SA-240 certification at enquiry if the vessel will be stamped.
A: It is a guide to harmonised standard grade compositions for wrought stainless steels, useful for cross-referencing grade designations between national systems. It is not a product specification, so material cannot be ordered or certified "to A959." Convert the enquiry to A240 or SA-240 and keep A959 as a cross-reference.
A: If the tank will hold anything corrosive and the welds will not be post-weld solution annealed, 304L is the safer specification because its lower carbon limits sensitisation in the heat-affected zone. You give up about 30 MPa of tensile minimum. Dual-certified 304/304L material satisfies both requirements from one heat and is worth asking about.
A: 4.76 mm (3/16 in) is the conventional dividing line, with sheet below it and plate at or above it. The distinction drives which tolerance table applies, which surface condition you receive, and often how the material is priced. Ask for the form you actually want by name.
A: Not meaningfully. A smoother surface holds fewer deposits, which helps in hygienic applications where cleanability is the concern, but it does not change how the alloy behaves in chloride service. If pitting is the risk, move to a molybdenum-bearing grade rather than a brighter finish.
A: Heat number, full chemical analysis against the named grade, tensile strength, yield strength, elongation, hardness, heat treatment condition, and the specification and edition certified to. If intergranular corrosion testing was a supplementary requirement, the ASTM A262 practice and result should appear as well. Check that the specification line on the certificate matches the specification line on your purchase order word for word.
Why prices differ between quotes, what moves the per-ton price and why quotations expire.
A: The indicative listing range is approximately USD 585–635 per metric ton as of August 2026. Position inside that band depends mainly on grade, thickness, tolerance and annealing condition. Delivered prices at your port will be higher by the freight and insurance component of the Incoterm used.
A: Indices report an average for a defined reference specification at a defined delivery point over a past period. A quotation prices your specification, on your delivery term, for a forward shipment. Both can be correct and different at the same time.
A: Galvanized and Galvalume coil are quoted on request rather than from a published band, because coating class and gauge move the per-tonne figure substantially. Zinc is between 1.5% and 17.5% of a coil's mass depending on those two variables alone.
A: Rebar has no published listing price and is quoted per specification. Grade, diameter, length or coil format, and destination standard all affect the figure.
A: The indicative listing range is approximately USD 440–568 per metric ton. The spread mostly reflects the range of section sizes rather than quality variation within a single section.
A: This varies by material family — CR Rod, HR Rod, and stainless bar are all considered "round bar" depending on context — and none currently carry a published price range. Request a quote specifying the exact grade.
A: An export offer prices raw material the mill has not yet bought, plus a freight rate that has not yet been booked. Both move. A long validity window is either priced with a risk margin or not honoured.
A: Not by itself. A larger order of one specification usually does. A larger order split across several specifications can price close to several smaller orders, because each specification is a separate production run and inspection lot.
A: Hot rolled sheet doesn't currently carry a published price range. Request a current quote rather than assuming it falls near cold rolled or PPGI pricing, since production process and cost basis differ.
A: No — these are separate products. Galvanized steel pipe has a published reference range (~USD 608–623/MT); galvanized coil (GI or Galvalume) does not currently have a confirmed published range.
A: Most commonly it's an Incoterms mismatch (FOB vs. CIF), a grade or coating specification difference, or a volume difference — confirm all three before assuming one quote is simply cheaper.
Read more: Cold Rolled Steel Prices in 2026: Ranges and Cost Drivers | Cold Rolled Steel Prices: Ranges and What Moves a Quote
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