What is S355JOWP?

S355JOWP, widely popular as Corten Steel, is a weathering structural steel that forms a protective rust-like layer when it comes it contact with the atmosphere. It is a part of the EN 10025-5 family of weathering steels and stays exposed to wind, moisture, and airborne pollutants for many years. This rust-like layer that it forms is called a Patina. And that patina keeps building on itself, layer after layer, until the surface becomes its own shield. In S355JOWP, the S is for structural steel, “JOWP” part signals a version that develops that patina more predictably, and 355 means the minimum yield strength of 355 MPa.

Panchdeep Metal supplies this grade along with its stainless steel product line, and many clients come looking for it when they need long-term reliability without constant maintenance and care. You see it used in heavy structures, but it also shows up in smaller architectural pieces that need a rustic look without losing strength. It holds that balance well.
A simple fact: it is built to stay outside.

S355JOWP Corten Steel Plates

Table of Contents

Mechanical Properties of S355JOWP Weathering Steel

Chemical Composition of Stainless Steel 303 Round Bar

Application of S355JOWP Weathering Steel

Why is S355JOWP is used for Weather Exposed Structure

Available Forms of S355JOWP

Why Choose Us for S355JOWP

Key Features of S355JOWP

Here are the 6 main characteristics of S355JOWP:

  • Strong resistance to atmospheric corrosion
  • The layer of patina generated due to rain and humidity seals the steel
  • The patina layer repairs itself
  • Long service life
  • Steady mechanical strength
  • Reliable stability

Mechanical Properties

The mechanical behaviour of S355JOWP makes it suitable for both load-bearing parts and wide, open panels.

Yield strength 355 MPa
Tensile strength 470-630 MPa
Elongation values 20% or more
Hardness moderate
Impact toughness high enough for various applications

The key point: it balances strength with workable toughness.

Chemical Composition of S355JOWP

The composition helps the alloy behave the way it does. Here is a simple table with the common range of elements found in this grade:

Element Typical Range (%) Role in Performance
Copper (Cu) 0.25 – 0.55 Helps the patina tighten and become more adhesive over time.
Chromium (Cr) 0.40 – 0.80 Strengthens the steel and slows down rust formation.
Nickel (Ni) 0.30 max Supports surface stability by improving resistance to airborne chemicals.
Phosphorus (P) 0.035 – 0.120 Makes the patina form faster and gives the steel a weathered look.
Carbon (C) 0.12 max Adds strength while keeping weldability manageable.
Manganese (Mn) 0.40 – 1.50 Improves toughness and helps the steel hold up against impact.

Copper and phosphorus lift the patina formation, while chromium and nickel help the surface hold that patina together. This blend is why structures made from S355JOWP keep ageing in a slow, controlled way rather than rusting through.

S355JOWP vs S355J2W vs S355JOW

To see how S355JOWP fits into the broader family, here is a simple comparison:

Property / Grade S355JOWP S355J2W S355JOW
Patina Formation Fast, stable Moderate Standard
Impact Properties Good at room temp Better at low temp Moderate
Weather Resistance High High Good
Cost Slightly higher Mid-range Generally lower
Common Uses Facades, bridges, sculptures Cold-region structures General weathering applications

S355JOWP stands out because of its appearance and its ability to form a dense patina more predictably. S355J2W performs better in colder zones. S355JOW stays closer to a baseline weathering steel with more standard performance.

Clients often choose between them based on climate, expected maintenance, and the structure’s visual needs.

Fabrication & Welding Guidelines

Fabricators appreciate that S355JOWP can be welded with common processes, though preheating is usually advised for thicker sections to keep heat-affected zones stable. Good welding practice ensures the patina forms evenly across welds instead of leaving pale or delayed-weathering patches.

Cutting works well with thermal or mechanical methods, and bending behaves predictably because the hardness sits at a workable level. The patina will develop on cut edges too, though sometimes a little slower during the early months.
Shops often perform light grinding before final installation to give the material a clean start for patina development.