Microstructure and Properties of Stainless Steel Wear-Resistant Surfacing Layer on 35 Steel

Literature Overview

This paper, published in Hot Working Technology (Volume 42, Issue 7, 2013, pages 161–162) by Li Ke, Wu Zhisheng, Liu Cuirong, and Song Xu from the School of Materials Science at Taiyuan University of Science and Technology, investigates the microstructure and hardness properties of a stainless steel wear-resistant layer deposited on 35 steel substrate using automatic submerged arc welding (SAW). The study was supported by the Shanxi Provincial Science and Technology Key Project (20100321084), Taiyuan University of Science and Technology Youth Fund Project (20113001), University-level UIT Project (XJ2010029), and Graduate Scientific Innovation Project (20111001).

Core Technical Findings

The study demonstrates that the hardness distribution of the surfacing metal corresponds directly to the microstructural changes across the deposit. The hardness of the surfacing layer achieved the expected target values, confirming the effectiveness of the automatic submerged arc welding process for producing wear-resistant stainless steel surfacing deposits.

The following table summarizes the key process and material parameters:

Parameter	Specification
Substrate material	35 steel (medium carbon steel)
Surfacing process	Automatic submerged arc welding (SAW)
Surfacing material	Stainless steel consumable
Key performance indicator	Hardness of surfacing layer
Quality criterion	Hardness meets design specification

Technical Interpretation

The automatic submerged arc welding process is well-suited for depositing thick, uniform surfacing layers on carbon steel substrates such as 35 steel. The flux coverage provides excellent shielding and allows for high deposition rates, making this process economically attractive for large-scale industrial applications. The use of stainless steel consumable on a carbon steel substrate creates a dissimilar material joint, where the dilution between the substrate and the surfacing deposit must be carefully controlled to achieve the desired properties.

The correlation between hardness distribution and microstructure is a fundamental metallurgical principle. In the fusion zone and heat-affected zone, the microstructure transitions from the substrate ferrite-pearlite structure to the surfacing layer microstructure, which may include martensite, austenite, and various carbide phases depending on the specific stainless steel composition. The hardness gradient across this transition reflects the changing phase composition and microstructural refinement.

Process and Quality Control Analysis

For automatic submerged arc surfacing of stainless steel on carbon steel, the following process parameters require careful control:

Process Parameter	Typical Range	Quality Impact
Arc voltage	25–35 V	Affects bead width and dilution
Welding current	400–600 A	Affects deposition rate and penetration
Welding speed	0.3–0.8 m/min	Affects bead geometry and cooling rate
Flux coverage	Adequate and uniform	Prevents oxidation and ensures shielding
Wire feed speed	Matched to current	Ensures stable arc and consistent deposition

The dilution rate in the first surfacing pass is typically higher than in subsequent passes. To achieve the target hardness in the final surfacing layer, multi-pass surfacing is often employed, with the first pass providing substrate bonding and subsequent passes building up the wear-resistant layer with progressively lower dilution.

Engineering Practice Implications

The application of stainless steel wear-resistant surfacing on 35 steel is common in industrial settings where both wear resistance and corrosion resistance are required. Typical applications include pump shafts, valve bodies, and structural components exposed to both abrasive and corrosive environments. The automatic submerged arc welding process allows for efficient, high-quality surfacing of large components, making it suitable for manufacturing and repair operations.

Quality assurance for this type of surfacing operation should include visual inspection for surface defects, hardness testing at multiple locations across the deposit, and potentially magnetic particle testing for subsurface defects. The hardness profile should be measured from the substrate surface through the surfacing layer to verify that the target hardness is achieved and that the transition zone is acceptable.

Study Insights and Reflections

This research confirms the effectiveness of automatic submerged arc welding for depositing stainless steel wear-resistant layers on carbon steel substrates. The direct correlation between hardness distribution and microstructure provides a clear metallurgical basis for process optimization. However, the study is relatively brief and does not provide extensive quantitative data on dilution rates, specific microstructural compositions, or detailed wear testing results.

For comprehensive engineering application, supplementary testing including microstructural analysis using scanning electron microscopy, chemical composition analysis of the dilution zone, and standardized wear testing would provide more complete performance data. The findings nonetheless validate the SAW process as a reliable method for producing wear-resistant stainless steel surfacing deposits, with the key insight being that hardness control through microstructure optimization is achievable and predictable in this process-material combination.