ASME SA210 A1 SUS630 65mm Seamless Boiler Tubes

Introduction

Grade 630 stainless steels are martensitic stainless steels that are precipitation hardened to achieve excellent mechanical properties. These steel achieve high strength and hardness following heat treatment. The heat and corrosion resistance of grade 630 are similar to that of grade 304 steels. This grades is also commonly referred to as grade 17-4PH.

One of the key benefits of this grade is that it is available in solution treated conditions, at which they can be easily machined and age-hardened to attain high strength. The age treatment of grade 630 is carried out at low temperatures, to avoid significant distortion. Therefore, this grade is used for applications such as the manufacture of long shafts that do not require re-straightening after heat treatment.

properties mentioned below pertain to commonly available grade 630 bar products in ASTM A564. The specifications may not be similar to other forms such as forgings and plates.

Composition

The compositional ranges of grade 630 stainless steels are displayed below:

Table 1. Composition ranges for grade 630 stainless steels

Mechanical Properties

The table below outlines the mechanical properties of grade 630 stainless steels:

Table 2. Mechanical properties of grade 630 stainless steels

*These values are specified for ASTM A564 and they apply only to certain size ranges. The specification should be consulted for the complete details of these properties.
Condition 900 is aged at 900°F (482°C), Condition 1150 is aged at 1150°F (621°C).
Solution treatment is at 927°C and cooled as required.

Physical Properties

The physical properties of grade 630 stainless steels are given in the following table:

Table 3. Typical physical properties of grade 630 stainless steels

Grade Specification Comparison

The typical grade specifications of 630 stainless steels are tabulated below:

Table 4. Grade specifications for grade 630 stainless steels

Possible Alternative Grades

The following table lists the possible alternative grades to 630 stainless steels:

Table 5. Possible alternative grades to 630 stainless steels

Applications

Some of the major applications of grade 630 stainless steels include:

• Engine components
• High strength and boat propeller shafts
• Plastic moulding dies
• Valves and gears