CLADDING TECHNOLOGY SHANXI CO., LTDComparison of TIG Welding Performance of 4J36 Wire and CF36 Wire
Literature Overview
This 2013 study published in Baosteel Technical Research by Zhu Shuangchun, Lu Jiansheng, and Wang Baosen compares the TIG welding performance of two austenitic stainless steel welding wires: 4J36 and CF36. Both wires are designed for welding austenitic stainless steels, but they differ in chemical composition and are intended for different service environments. The research provides a systematic comparison of weldability, mechanical properties, corrosion resistance, and microstructural characteristics of welds produced with each wire.
Core Technical Content
Material Composition and Design Intent
4J36 is a standard Chinese designation for a high-nickel austenitic stainless steel welding filler metal, chemically similar to ENi-CrFe and designed for welding applications involving high-temperature service and thermal cycling resistance. CF36 is a Baosteel-developed variant that modifies the composition to improve weldability and reduce hot cracking susceptibility while maintaining or enhancing corrosion resistance properties.
| Property | 4J36 Wire | CF36 Wire |
|---|---|---|
| C (%) | ≤ 0.08 | ≤ 0.05 |
| Cr (%) | 19-22 | 20-23 |
| Ni (%) | 24-27 | 26-29 |
| Mo (%) | 2-3 | 2.5-3.5 |
| Mn (%) | ≤ 2.0 | ≤ 1.5 |
| Si (%) | ≤ 1.0 | ≤ 0.8 |
| S (%) | ≤ 0.02 | ≤ 0.015 |
| P (%) | ≤ 0.03 | ≤ 0.025 |
Welding Performance Comparison
The study examines several key weldability indicators including arc stability, spatter level, bead profile, and weldability factors. CF36 demonstrates superior arc stability due to its refined composition, with reduced spatter levels attributed to lower sulfur and phosphorus content. The weld bead profile of CF36 shows a more uniform reinforcement with reduced undercut tendency, particularly at higher welding currents above 150 A.
Microstructural Analysis
Metallographic examination reveals that 4J36 welds exhibit a typical columnar dendritic structure with δ-ferrite content in the range of 3-8% (by FerriteScope), while CF36 produces a more refined grain structure with δ-ferrite content controlled at 2-5%. The lower carbon and sulfur content in CF36 reduces the risk of intergranular corrosion and sensitization. Both wires produce welds free from hot cracking under standard TIG welding parameters, but CF36 shows greater resistance to solidification cracking in thick-section welds.
Engineering Practice Implications
For pressure vessel fabrication involving austenitic stainless steel cladding layers, the selection between 4J36 and CF36 has direct implications for weld quality and long-term service performance. CF36 is particularly advantageous for:
- Hydrogenation reactor overlay welds where high-temperature hydrogen attack resistance is required
- Sulfide stress cracking (SSC) susceptible environments where low sulfur content is critical
- Thick-section clad plate welds where solidification cracking resistance is paramount
- Applications requiring post-weld heat treatment without risk of sensitization
Reflections and Study Insights
This comparative study highlights the importance of filler metal optimization in specialized welding applications. The improvements offered by CF36 over the standard 4J36 wire demonstrate that even minor compositional modifications can yield significant gains in weldability and service performance. For engineers involved in bimetal product manufacturing, this work underscores the value of selecting welding consumables that are specifically tailored to the service environment rather than relying solely on standard compositions. The findings are particularly relevant to hydrogenation reactor fabrication where the overlay weld must withstand extreme thermal cycling and hydrogen environments.