00Cr25Ni7Mo4N welding performance

内容

Introduction

The welding performance of Tubing of 0Cr25Ni7Mo4N has been researched for the past few decades due to its resistance to corrosion and excellent strength properties. This alloy is often used in areas such as offshore drill rigs, chemical and petrochemical plants, and medical applications. While the alloy provides excellent mechanical properties, welding poses its own set of challenges due to its resistance to thermal cracking and oxidation. This document provides an overview of the welding performance of 0Cr25Ni7Mo4N and the various parameters that need to be taken into consideration when welding this alloy.

Weldability

0Cr25Ni7Mo4N is a very tough and economic solution for the welding of pipelines and other structures, such as those found in the oil and gas industry. The alloy can be easily welded using the most commonly used processes, such as shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW), gas metal arc welding (GMAW), submerged arc welding (SAW), and electrical resistance welding (ERW).

Although the alloy is relatively easy to weld, its resistance to thermal cracking and oxidation must be taken into consideration. The joint preparation should be done carefully and the correct filler materials must be selected in order to avoid thermal cracking and oxidation. In order to make sure that the weld is free of defects, it is important to do regular visual inspections during the welding process.

The weldability of 0Cr25Ni7Mo4N depends on the filler material chosen for the weld. The most suitable filler materials for the welding of this alloy are ER309L and ER310. Other commonly used filler materials such as 316L and 308L can also be used, but the welding parameters should be adjusted accordingly.

Welding Parameters

When welding 0Cr25Ni7Mo4N, it is essential that the welding parameters are tweaked according to the filler material chosen for the weld as well as the welding technique employed. For SMAW, the optimal welding current ranges between 80A and 100A and the arc voltage should range between 19v and 22v. For GTAW, the optimal welding current will vary between 65A and 85A, while the arc voltage should range between 18v and 22v.

For gas metal arc welding, the optimal welding current ranges between 80A and 90A and the arc voltage should range between 25v and 28v. For submerged arc welding, the welding current should be set between 80A and 90A and the arc voltage should range between 27v and 30v. Finally, for ERW, the optimal welding current should range between 55A and 60A, while the arc voltage should range between 15v and 16v.

Conclusion

0Cr25Ni7Mo4N is an alloy that provides excellent mechanical properties and resistance to corrosion. Its weldability is excellent and the alloy can be welded using the most commonly used processes. However, care must be taken when selecting the filler material and adjusting the welding parameters in order to avoid thermal cracking and oxidation. A regular visual inspection during the welding process is also recommended.

Weldability of 1.4864 (TP 310, 08Cr25Ni7Mo4N)

1.4864 is a heat resistant austenitic stainless steel (254 SMO) containing 25% chromium and 7% nickel. It offers improved creep strength and stability at elevated temperatures over 304 stainless steel and higher resistance to pitting corrosion.

It can be welded fairly easily and with the right parameters has a very good mechanical strength but due to its high carbon levels it can be prone to hot cracking. Use only low carbon rods, coated electrodes with ceriated or thoriated tungsten, or solid wire with either 100% or 75% argon/25% CO2 shielding gas, depending on the position. Care must also be taken not to exceed 800°C as temperatures above this can cause sensitization and embrittlement.

When it comes to forming, 1.4864 has a high plastic deformation tolerance due to its austenitic structure providing greater formability than ferritic and martensitic stainless steels.

1.4864 has superior corrosion resistance in acid environments compared to other stainless steel grades, however it is not usually resistant to high chloride concentrations. In order to maintain better corrosion resistance it would be recommended to use a liquid or an air cooled post weld heat treatment.

In conclusion, 1.4864 is a heat resistant austenitic stainless steel which is fairly easily welded if care is taken to use the right parameters. It has superior corrosion resistance in acid environments but not in high chloride concentrations. It also has a high plastic deformation tolerance which makes it suitable for forming.