Difference Between 304H and 347H Stainless Steel Tubes

What is Stainless Steel?

Stainless steel is a versatile composition of a steel alloy and a small percentage of chromium — the addition of chromium increases the material’s corrosion resistance, a trait that earned stainless steel its name. Since stainless steel has low-maintenance, oxidation resistant, and does not affect other metals with which it comes into contact, it is widely used in a wide range of applications, particularly in piping and tubing manufacturing.

Let’s learn more about the differences between 304H and 347H Stainless Steel Tubes.

304H Features and Applications.

Features:

Stainless steel 304H has excellent cold deformation properties, as well as bending and welding process performance, corrosion resistance, high durability and structural stability, and excellent durability and structural stability. The temperature can be used at 650 degrees Celsius, and the oxidation temperature can reach 850 degrees Celsius.

Type 304H has a higher carbon content, making the steel more suitable for use in high-temperature applications. It is an austenitic chromium-nickel steel alloy with a higher carbon content that leads to a higher tensile and yield strength. Because of the grade’s heat resistance, it is recommended for use in ASME pressure vessels in working service above 525 °C.304H has greater strength at high temperatures and may be the steel of choice when both high-temperature resistance and corrosion resistance are required.

Application:

Stainless steel, grade 304H Tubes are used in industrial boilers, pressure vessels, heat exchangers, pipelines, and condensers and are mainly found in the oil refining, gas, and chemical industries. In addition, the material is extensively used in the power generation industry.

347H Features and Applications.

Features:

Stainless steels 347H Tubes are high-alloy steels with higher corrosion resistance than other steels due to the presence of large amounts of chromium ranging from 4 to 30%. Based on their crystalline structure, stainless steels are classified as martensitic, ferritic, or austenitic. It has strong heat resistance, intergranular corrosion resistance, welding performance, and corrosion resistance in alkali, seawater, and other acids. These stabilized alloys 347H and 347HFG have higher elevated temperature permissible stresses for ASME Boiler and Pressure Vessel Code applications. They also belong to another group known as precipitation-hardened steels, which are a mix of martensitic and austenitic steels.

The stainless steel grade 347H is way harder than the stainless steel grade 304H.

Application:

Large boiler super heater tubes, reheater tubes, steam lines, and petrochemicals heat exchangers In boiler tubes, the maximum allowable oxidation temperature is 750 °C.