引言
一份只写 GI coil, 0.45 x 1000, Z80 or Z140 OK 的询价单并没有冻结镀层。一家钢厂报 EN 10346 Z140。另一家用同一 FOB 填 Z80 并写 “equivalent zinc”。第三家在形式发票上印 G90，在 EN 10204 3.1 MTC 上印 Z140。厚度可以对上。锌花可以对上。带钢上的锌对不上。
这是给进口商准备的规格拆解，适用于采购 DX51D 镀锌卷 用于屋面、墙面、风管和出口库存。它是采购指导，不能替代订货版本的 EN 10346、ASTM A653/A653M、JIS G 3302、EN 10143 或 ISO 9223。成型牌号仍要单独一行：G550 镀锌卷 是屈服级别，不是锌层级别。当钢厂在这些字段下更换镀层质量时，回到本文核对。
让三份报价无法比较的镀层行
快速技术摘要（精选摘要直接答案）： Z80、Z140 和 Z275 表示双面合计最小锌层质量，不是采购订单上的微米数，也不是 100% 等同库存。比较 FOB 前先冻结标准（EN 10346、ASTM A653 或 JIS G 3302）、镀层代号，以及试验方法（triple-spot versus single-spot）。
镀层行只写绰号时，标书就失败了。Z275 是质量。G90 是盎司质量。20 um 只是指导厚度，不是称重-剥离-称重结果。询价单只要放开这三种语言中的任何一种，能拍出亮卷的最低价钢厂就会中标。
| Missing RFQ field | What the mill will fill | Why the three quotes cannot be ranked |
|---|---|---|
| Standard omitted (“GI / HDG coil”) | EN 10346, ASTM A653, or a mill card | Z140 and G60 are not the same test gate |
| Designation omitted (“heavy zinc”) | Z80, Z140, or leftover Z100 | Outdoor duty and indoor ducting share one price |
| Test method omitted | Triple-spot average, single-spot, or a handheld gauge | A passing micron photo can fail ASTM A653 Table 1 |
| Which surfaces | Total both sides vs one-side minimum | Differential coating hides a thin exposed face |
| ISO 9223 site class | Whatever zinc the mill already has | C2 indoor stock is sold into a C4 coastal PO |
把镀层写成可粘贴的文案块，而不是口头商量。下文就是该文案块需要的字段清单。ASTM G90 不是口头 “heavy zinc”。
Z80、Z140 和 Z275 实际冻结的内容
连续热镀锌板的镀层代号是 双面合计最小镀层质量，通常用 三点试验 证明。它们并不保证每一面各占一半锌，也不是 EN、ASTM 与 JIS 之间 100% 等同。
| Designation | System buyers actually write | Minimum total both sides (triple-spot) | Typical guidance thickness per side | Do not treat as |
|---|---|---|---|---|
| Z80 | Commercial offer; often JIS-style Z08 | 80 g/m2 if the mill accepts that code | About 5-6 um guidance only | An EN 10346:2015 listed zinc class |
| Z140 | EN 10346 Z140 | 140 g/m2 | About 10 um | ASTM A653M Z120 or Z180 |
| Z275 | EN 10346 Z275 / ASTM A653M Z275 | 275 g/m2 | About 20 um | A batch-galvanized ISO 1461 micron call-out |
| G60 | ASTM A653 G60 | 0.60 oz/ft2 (about 183 g/m2) | Guidance only | Z140 |
| G90 | ASTM A653 G90 | 0.90 oz/ft2 (about 275 g/m2) | About 20-21 um if the split is even | A free upgrade from Z140 |
SSAB 等钢厂产品卡按 EN 10346:2015 列出 Z100 到 Z600 的锌层，Z140 为 140 g/m2，Z275 为 275 g/m2，均为三点试验下双面合计最小质量。指导厚度只是指导。采购订单应冻结克/平方米（或 oz/ft2），而不是仓库测厚仪。
ASTM A653 Table 1 对如何证明该质量更严。对 G90，三点平均必须达到 0.90 oz/ft2 双面合计，单点合计必须达到 0.80 oz/ft2，任一单面通常不少于 0.32 oz/ft2（约单点合计的 40%）。GalvInfo 换算 1.00 oz/ft2 = 305 g/m2，因此 G90 与 Z275 相邻。相邻不是同一身份。钢厂双盖 Z275 / G90 时，仍须通过你 PO 上写明的试验方法。
Z80 是最容易漏的字段。公布 EN 10346 锌层表的建筑目录把 Z80 标成 not included in the standard，并把 Z100 作为首个列出的级别。出口报价仍打印 Z80，因为它便宜、易成型，并接近 JIS Z08。若图纸引用 EN 10346，应要求钢厂写明 Z100、Z140 或 Z275。不要让 Z80 继承 EN 编号。
不要在表格里把 Z140 换成 G60 并宣布完成。G60 约为 183 g/m2。Z140 是 140 g/m2。钢厂卡上最接近 Z140 的 ASTM 家族常常是 Z120 或 G40，不是 G60。核对订货版本；不要发明一行等效。
ISO 9223 腐蚀性属于询价字段，不是钢厂绰号
在给定大气中，锌寿命随厚度增加。这不会把 Z275 变成沿海质保，也不会把 ISO 9223 C5 变成钢厂能轧出来的镀层代号。
| ISO 9223 class buyers name | Typical atmosphere language | What a GI coil RFQ should freeze instead of a year-life slogan |
|---|---|---|
| C1-C2 | Heated indoor / rural inland | Z80 or Z100 only if the drawing is indoor and cut edges stay dry |
| C3 | Urban / light industrial / low-salinity coast | Z140 or Z275 as the project names; not “Z80 heavy zinc” |
| C4-C5 | Industrial wet / moderate-to-high chloride | Z275 is often still a light coil coating; ask whether AZ, ZM, or batch HDG is the specified system |
| CX | Offshore / extreme | Continuously galvanized DX51D coil is rarely the specified system |
把 EN 10346 锌层映射到腐蚀性的钢厂文献，比贸易层口号更保守。一份把热浸锌映射到 EN 55634-1 的产品说明，把 Z275（约每面 20 um）放在大约 C3 工况，而不是 C5。把它当作钢厂指导，核对项目规范，不要用 Z140 形式发票去买 25 年沿海故事。
若现场氯离子高，下一个问题是镀层 化学，而不只是质量。锌（GI）、55% 铝锌、锌铝镁是不同体系。本文冻结镀锌卷上的 Z 质量。它不把 Z275 转换成 Galvalume 或 ZAM 替代。
油漆不会改写锌行。PPGI 彩涂卷 仍需在基板上写明金属镀层（DX51D+Z140、DX51D+Z275 或订货级别）。RAL 9002 是颜色目标，不是镀层质量。
基板化学、成型牌号和厚度仍在同一卷上
镀层质量坐在钢基板上。Z275 钢印不能冻结 DX51D，DX51D 钢印也不能冻结 Z275。两者写在同一询价行。
| Substrate family | Standard language | C % max (typical table) | Mn % max | P % max | S % max |
|---|---|---|---|---|---|
| DX51D | EN 10346 DX51D+Z | 0.18 | 1.20 | 0.12 | 0.045 |
| S550GD | EN 10346 S550GD+Z | 0.20 | 1.70 | 0.10 | 0.045 |
| SGCC | JIS G 3302 SGCC | Confirm ordered edition | Confirm | Confirm | Confirm |
| CS Type B | ASTM A653 CS Type B | Confirm ordered edition | Confirm | Confirm | Confirm |
把该表当作提醒：化学成分属于 PO。核对 EN 10346 订货版本；不要把 DX51D、SGCC 与 CS Type B 当成 100% 等同。
| Family | Yield / tensile direction (confirm ordered edition) | Elongation / forming | Coating note |
|---|---|---|---|
| DX51D+Z | Tensile often discussed as 270-500 MPa; no 550 MPa min | Elongation is the acceptance field for profiling and bending | Z80 to Z275 can all sit on this grade |
| SGCC | Commercial GI; not a 550 MPa class | Same job family as DX51D on many export offers | JIS coating codes (Z08, Z12, Z27) are not EN nicknames |
| S550GD+Z / mill G550 | Yield min 550 MPa class | Low leftover stretch; high-rib roofing | Zinc class is still a separate field |
| SGCH full hard | Full-hard GI, not DX51D | Poor lock-seam stretch | SGCH carbon steel coil is a hardness family, not a zinc family |
| Coil field | What to freeze on the PO | Typical export range (confirm mill card) | Bid failure if omitted |
|---|---|---|---|
| Thickness basis | Base metal or total coated product | 0.30-1.50 mm common for GI coil | 0.45 mm G550 rib vs 0.45 mm DX51D base metal |
| Thickness tolerance class | EN 10143 / ASTM A924 class as ordered | Special vs normal class | Mill ships the looser class at the same price |
| Width / edge | Mill edge or slit edge; width +0/-0 or named | 600-1250 mm common | Slit-edge camber on a lock-seam line |
| Coil ID / OD / mass | ID 508 mm or 610 mm; max OD; kg per coil | 3-8 MT on thin GI; 20GP payload 25-28 MT | Eye-to-wall coils that will not fit the cradle |
山东出口卷的一线规律：PI 写 DX51D+Z, Z80/Z140, 0.40 x 1000。钢厂装 Z80，因为斜杠看起来像买方可选项。MTC 镀层栏打印低于 100 g/m2 的合计质量。C3 工业区的加工厂随后索赔白锈，因为白锈看得见、锌质量看不见。若 PO 写明 Z140 而证书无法证明，就在钢厂扣卷。
表面、包装和 MTC 字段必须点名镀层
表面用语是轻镀层的藏身之处。Zero spangle 和 regular spangle 不会把 Z140 变成 Z275。钝化和涂油改变 20GP 中的白锈风险；它们不加锌克数。
| Surface / coating field | Options to freeze | Why it belongs next to Z80 / Z140 / Z275 |
|---|---|---|
| Spangle | Zero / minimized / regular | Appearance only; not a mass upgrade |
| Surface quality | As-coated A / improved B (EN language) | Skin-pass for painting is not extra zinc |
| Passivation | Cr-free / chromated / none | Unpassivated Z275 still white-rusts in a hot container |
| Oiling | Dry / light oil | Dry coil + long sea transit is a packing claim waiting to happen |
| Differential coating | Equal both sides vs named g/m2 per face | A thin exposed face fails first |
| Packing field | Seaworthy default to name | Hold point |
|---|---|---|
| Wrap | VCI paper + plastic + outer steel sheet | Bare OD wrap on a rainy yard |
| Edge | Inner and outer metal edge protectors | Cut OD that starts white rust in week one |
| Straps | At least 3 circumferential + 4 radial steel straps | Collapsed eye after stuffing |
| Desiccant | Named silica-gel mass per coil | ”Anti-rust packing” with no packet count |
| Stowage | Eye-to-sky or eye-to-wall; wooden cradle; 1x20GP 25-28 MT | Mixed stowage that rubs the zinc off the OD |
| MTC 3.1 field | Must print | Reject / hold if |
|---|---|---|
| Standard + coating designation | EN 10346 Z140, ASTM A653 G90, or the PO string | ”GI” or “Z80/Z140” as a range |
| Coating mass | Total both sides, unit g/m2 or oz/ft2 | Micron-only remark with no mass |
| Test method | Triple-spot and/or single-spot as ordered | Warehouse gauge photo only |
| Heat / coil identity | Heat number matching stencil and packing list | Heat on MTC, different heat on tag |
| Substrate grade + mechanicals | DX51D / SGCC / CS plus tensile / elongation as ordered | Coating matches, grade swapped |
| Inspection representative | EN 10204 3.1 issuer independent of production | Unsigned mill list |
第三方检验属于同一扣货点。SGS、BV 或 TUV 可按 ASTM A90/A90M 切试样做称重-剥离-称重，并核对平均值是否为订货级别。发亮的外径不是该试验。EN 10204 3.1 材质证明书做法 是纸面轨迹；PSI 是卷面核对。
镀层质量采购订单复制块
把此块粘进询价。删掉你不要的选项。不要在 Z80 和 Z275 之间留斜杠。
- Product: continuously hot-dip galvanized steel coil, not batch HDG after fabrication.
- Standard / grade: EN 10346 DX51D+Z (or ASTM A653 CS Type B / JIS G 3302 SGCC as the drawing names). Not dual-stamped against S550GD or mill G550 unless accepted.
- Coating designation: Z140 or Z275 or G90 — one code only. Z80 only if the drawing is indoor and the standard is not EN 10346.
- Coating test: minimum total both sides by triple-spot; single-spot gate as in the ordered ASTM A653 / EN 10346 table. Weigh-strip-weigh referee (ASTM A90/A90M or the EN method named).
- Split: equal both sides unless a differential coating is named per face.
- Surface: zero or regular spangle; Cr-free passivation; oiled or dry as named.
- Size: thickness (state base metal or total coated) x width x coil ID 508/610 mm; EN 10143 / ASTM A924 tolerance class.
- ISO 9223 site class on the RFQ header (C2 / C3 / C4), not as a mill zinc nickname.
- Documents: EN 10204 3.1 MTC with heat number, coating mass, test method, and substrate mechanicals. TPI coupons allowed.
- Packing / lot: VCI + edge guards + named strap count; 1 x 20GP (25-28 MT); dispatch 7-15 days for standard sizes.
若钢厂回答 “Z80 equivalent to Z140” 或 “G90 / Z140 same”，报价就不可比。把文案块发回去，先冻结一个镀层代号。宽度常见 600-1250 mm，厚度常见 0.30-1.50 mm；薄规格卷重常见 3-8 MT。SGCH 全硬镀锌卷 是硬度家族，不是锌层家族。
结论
Z80、Z140 和 Z275 是连续镀锌卷上的锌层质量代号。它们不是钢厂绰号，不是室内/户外口号，也不是 EN 10346、ASTM A653 与 JIS G 3302 之间 100% 等同。冻结一个代号、一种试验方法、一个基板牌号和一个 ISO 9223 场地等级。然后在装箱前，在 EN 10204 3.1 MTC 上读这四个字段。
计划下单或需要技术核对？
如果您正在采购 镀锌钢卷（Z80 / Z140 / Z275 或 G90），或需要钢厂按项目大气确认镀层质量：
- 快速技术报价：标准规格支持从 1 x 20GP 集装箱（25-28 MT） 起订，7-15 天发运。请通过我们的 在线询价表 提交牌号、镀层代号、厚度 x 宽度和数量。
- 质量保证：每笔订单配备真实 EN 10204 3.1 Mill Test Certificates，炉号可追溯。欢迎 SGS、BV、TUV 第三方检验。
- 紧急询盘：直接联系山东出口台 WhatsApp +86 151 5311 2221 确认规格。
