White Rust on Galvanized Steel: Causes and Prevention
Why white rust forms on galvanized steel in transit, how to tell it from red rust and mill residue, how to judge severity, and who controls prevention.
Steel Knowledge
Technical guides on Chinese steel grades, international standards and product selection.
Nominal Pipe Size (NPS) vs Outside Diameter Explained
NPS is a name, OD is a measurement. Why a pipe ordered by nominal size will not measure that size, how DN, NB and IPS fit in, and what to put on the order.
C Purlin vs Z Purlin: Section Shape and When to Use Each
How a C purlin and a Z purlin differ in section shape, lapping and continuity, which suits roof purlins or wall girts, and how to write a purlin order.
ASTM A106 vs A53 vs API 5L: Which Pipe Specification Do You Need?
A106 vs A53 vs API 5L compared by scope, manufacturing route and quality level, plus why a certificate naming the wrong specification gets rejected.
Cast Iron Pipe vs Steel Pipe: Sizes, Lifespan and Uses
Cast iron pipe vs steel pipe compared: how each is sized, what really decides service life, how the joints differ, and which duty each material suits.
JIS SS400 Steel: Equivalent Grades and What They Mean
SS400 is named from tensile strength, not yield. Here is what JIS G3101 guarantees, the accepted equivalents, and when substitution is unsafe.
Structural Steel Fabrication Tolerances: What Buyers Should Specify
Fabrication tolerances for structural steel cover length, straightness, hole position and weld distortion, on top of mill tolerances. Here is what to specify.
What Steel Are Shipping Containers Made From?
Shipping containers are built from weathering steel: which grades sit behind the word Corten, where each part of the box uses steel, and how to specify it.
Wire Rod: Grades, Specifications and Applications
Wire rod explained: how it differs from round bar and rebar, what the grade designation on the mill certificate means, and what a specification must settle.
Pickled and Oiled Steel: What HRPO Means for Buyers
Pickled and oiled steel explained: what pickling removes, why the oil matters, HRPO against hot rolled black and cold rolled, and what to put on the order.
Hot-Dip Galvanizing Standards: ASTM A123, EN ISO 1461 and GB/T 13912
Hot dip galvanizing standards compared: which covers fabricated steel, coil, sheet and fasteners, what inspection checks, and how to write the purchase order.
Steel Pipe Wall Thickness Tolerance Standards
Which standards set steel pipe wall thickness tolerance, why the delivered wall runs thin, how it is measured and what to write into the purchase order.