Grinding Performance of 20Cr10Ni Stainless Steel Overlay Layer on Nuclear Power High-Pressure Vessel Interior Surface

Literature Overview

Published in 2008 in Machine Tool and Hydraulics, this paper by Huang Xuesong, Huang Yun, and Wang Yang from Chongqing University presents a systematic investigation into the grinding performance of austenitic stainless steel 20Cr10Ni overlay layers applied to the interior surfaces of nuclear power high-pressure reactor vessels. Funded by the National 863 Program, the research addresses a critical manufacturing challenge in nuclear power equipment fabrication where precision surface finish is essential for radiation resistance, corrosion resistance, and stress corrosion resistance performance.

Technical Background and Requirements

Nuclear reactor pressure vessels require austenitic stainless steel overlay layers on their interior surfaces to provide resistance against radiation-induced embrittlement and to maintain corrosion resistance in the high-temperature, high-pressure water environment. The overlay layer must be ground to achieve specific surface roughness values (typically Ra ≤ 0.4 μm for critical areas) while avoiding surface damage, work hardening, and residual tensile stresses that could compromise the corrosion resistance of the overlay.

The 20Cr10Ni austenitic stainless steel presents unique grinding challenges due to its:

Low thermal conductivity, leading to concentrated heat generation at the grinding interface
High work hardening rate, which dulls abrasive grains rapidly
Low elastic modulus, resulting in higher material deformation during cutting
Chemical affinity with abrasive materials, promoting chemical wear of the grinding wheel

Core Technical Findings

Abrasive Belt Wear Mechanism Analysis

The authors conducted theoretical analysis of the heavy-duty abrasive belt wear characteristics during grinding of 20Cr10Ni overlay layers. The fundamental finding was that the normal contact pressure on individual abrasive grain cutting edges was insufficient to achieve effective material removal. This led to premature dulling of micro-crystalline abrasive grains that could not be broken off and renewed in a timely manner, thereby weakening the self-sharpening capability of the abrasive belt.

Grinding Parameter	Effect on Performance	Recommended Range
Normal pressure	Insufficient pressure causes grain dulling	Higher pressure to activate cutting
Grinding speed	Low speed reduces material removal rate	Moderate increase improves efficiency
Feed rate	Excessive feed increases surface damage	Controlled feed for finish quality
Grain size	Coarse grains wear faster on austenitic SS	Medium-fine grains for balance
Belt grade	Standard grades show poor performance	Heavy-duty reinforced belts required

Experimental Results

Testing was conducted using a dedicated abrasive belt grinding test machine equipped with comprehensive measurement systems. The results demonstrated that:

Increasing the normal grinding pressure significantly improved material removal rate by activating the cutting action of individual abrasive grains
Appropriate increases in grinding speed enhanced the cutting effectiveness and promoted grain fracture and self-sharpening
The combination of higher pressure and moderate speed increase achieved optimal grinding efficiency while maintaining acceptable surface quality
The heavy-duty abrasive belt showed superior performance compared to standard belts due to reinforced backing and improved grain bonding

Process Optimization and Engineering Application

The research proposed an optimized heavy-duty abrasive belt grinding process specifically for nuclear reactor vessel overlay layers. The key process parameters were established through systematic experimentation, providing practical guidance for manufacturers of nuclear power equipment.

The study's significance extends beyond the specific application to nuclear power vessels. The grinding of austenitic stainless steel overlay layers is a common challenge in:

Chemical processing equipment
Food processing equipment requiring sanitary surfaces
Pulp and paper industry equipment
Marine applications requiring corrosion-resistant surfaces
Medical device manufacturing

Study Insights and Implications

The fundamental insight from this research is that the root cause of poor grinding performance on austenitic stainless steel is not simply a material property issue but rather a mechanical interaction issue between the abrasive grain and the workpiece. The insufficient normal contact pressure on individual grain cutting edges leads to a vicious cycle of dulling without renewal. This understanding has direct implications for grinding process design: rather than simply changing abrasive materials, the process parameters must be adjusted to ensure sufficient cutting force at the grain level. The research methodology, combining theoretical analysis with systematic experimentation, provides a model approach for investigating grinding performance in challenging material-process combinations.