JIS G3106—1999 rolled steels used in welding structure are of two types – hot-rolled and cold-rolled. Hot rolled steel grades are SM400A/B, SM490A/B/C, SM520B/C and SM570. Hot rolled steels are characterized by their excellent weldability due to their low alloy content. Hot rolled steel have a wide range of applicability and are used in a variety of structural and engineering applications.
Cold rolled steel grades are SM400A/B/C, SM490A/B/C, SM520B/C and SM570. Cold rolled steel is produced by cold rolling process, by which the thickness of the steel can be reduced by up to 50%. It has excellent weldability and it is suitable for welding with most types of welding techniques. Cold rolled steels are highly versatile and they are used in a wide range of applications.
The chemical composition of the two types of rolled steels is given in the table below:
|Hot Rolled Steel | Chemical Composition (%) |
|-----------------|--------------------------|
| C | ≤ 0.22 |
| Si | 0.18 - 0.60 |
| Mn | 0.50 - 1.50 |
| P | ≤ 0.035 |
| S | ≤ 0.035 |
|Cold Rolled Steel | Chemical Composition (%) |
|------------------|--------------------------|
|C | ≤ 0.18 |
| Si | 0.15 - 0.60 |
| Mn | 0.50 - 1.50 |
| P | ≤ 0.030 |
| S | ≤ 0.030 |
The mechanical properties of the two types of rolled steels are also provided in the table below:
|Hot Rolled Steel | Mechanical Properties |
|-----------------|----------------------|
| Tensile Strength | ≥ 400MPa |
| Yield Strength | ≥ 250MPa |
| Elongation | ≥ 25% |
|Cold Rolled Steel | Mechanical Properties |
|------------------|----------------------|
| Tensile Strength | ≥ 370MPa |
| Yield Strength | ≥ 235MPa |
| Elongation | ≥ 25% |
JIS G3106—1999 rolled steels are essential in various structural and engineering applications. They are used in the construction of buildings, bridges, pipeline, factory halls and ships. From automotive industry applications to structural and civil engineering, these rolled steels offer a variety of benefits to engineers. They are easier to shape and bend than standard steels and are also less brittle. They are also more durable than other steels and have a higher strength-to-weight ratio.
In conclusion, JIS G3106—1999 rolled steels are used in welding structures and have a wide range of applications. They have excellent weldability and offer many benefits for engineers and designers. They provide strength and durability at a relatively low cost.
