4330V Stop-and-Go Heat Treatment Project

Project Background:

• 4330V is a high-strength alloy steel widely used in oilfield and industrial applications requiring exceptional toughness and reliability.
• Achieving uniform heat treatment in large-diameter bars (e.g., 7.5") is critical to ensure consistent mechanical properties across the cross-section.
• During my internship at Nucor Steel Memphis, I identified an opportunity to enhance thermal uniformity during heat treatment without requiring major equipment changes.
• I independently proposed and designed a “stop-and-go” rotational method, where the bar is periodically paused and rotated during furnace processing to simulate extended soak time.
• The approach aimed to improve heat penetration and transformation consistency throughout the bar, especially at mid-radius and center locations.
• This project allowed me to apply process innovation and metallurgical analysis to real-world production challenges, contributing directly to ongoing quality improvement efforts at the plant.

Process and Method

• Introduced a "stop-and-go" movement pattern during furnace processing, where bars were rotated and paused at intervals to simulate extended thermal exposure across the cross-section.
• Determined rotation timing and holding durations in coordination with automation and electrical teams.
• Brinell Hardness was measured at the surface, mid-radius, and center along with microstructrual evaluation at each location.

Key Results:

• Hardness Improvement: Surface hardness increased by up to +12 HBW; mid-radius and center showed improvements of up to +9 and +5 HBW respectively.
• Microstructural Uniformity: Enhanced consistency of tempered martensite and reduced evidence of banding.
• Process Validation: Demonstrated that simple timing changes can lead to measurable property improvements without major equipment modifications.

 

Engineering Insights

• The trial highlighted the relationship between furnace movement patterns and thermal uniformity.
• Improved transformation homogeneity can be achieved even in complex geometries with process innovation.
• Provided data supporting further development of movement-based heat treatment enhancements.

Tools & Skills Gained:

• Heat treatment process design
• Cross-functional coordination with maintenance and automation teams
• Metallographic sample prep and microstructure analysis
• Hardness testing and process validation

This project sharpened my ability to approach metallurgical challenges with both practical experimentation and data-driven analysis. It also reinforced the importance of collaboration across operations, engineering, and quality to implement and assess meaningful process innovations.