SIG Ultrasonic Hardness Tester: Non-Destructive & Portable Solution for Roll Hardness Measurement

Introduction:
As a core tool in steel rolling production, the hardness of rolls directly determines wear resistance, thermal crack resistance, and final sheet surface quality. However, traditional hardness testing methods either damage expensive roll surfaces with excessive indentations or are too bulky for on-site operation. Sinowon introduces an ultrasonic hardness tester based on non-destructive measurement technology. With a portable design, it provides an efficient and accurate hardness measurement solution for various types of rolls.

Industry Pain Points: The Dilemma of Roll Hardness Testing

In the metallurgical and paper industries, rolls are large and valuable components, weighing from several tons to over a hundred tons. For a long time, companies performing roll hardness testing have faced three major challenges:

1. Risk of Surface Damage

Traditional bench-top hardness testers such as Brinell and Rockwell use high test forces, leaving visible indentations on roll surfaces. For rolls that have already been precision-finished, these indentations may cause stress concentration and become the source of future fatigue cracks.

2. Low Efficiency and Poor Accuracy

Large rolls cannot be moved into laboratories. In the past, companies relied on Shore or Leeb hardness testers. However, these methods are highly susceptible to interference from oil contamination, surface roughness, and vibration, resulting in high data dispersion. Frequent hardness value conversions are required, which often leads to disputes.

3. Coating Measurement Failure

Modern rolls often undergo chrome plating, copper plating, or nitriding treatment (hardness can reach over 1000 HV), but the coatings are extremely thin. Due to principle limitations, traditional portable hardness testers cannot accurately measure the true hardness of such thin coatings.

Solution: Technical Advantages of the UCI Method

Sinowon ultrasonic hardness testers (such as the SU-300 series and SU-320R) are based on the Ultrasonic Contact Impedance (UCI) principle, perfectly matching roll testing requirements:

• Non-Destructive Measurement: Using a diamond indenter with a test force of only a few Newtons (2 kgf–10 kgf), the indentation left on the roll surface is extremely small (observable only under high magnification), without affecting subsequent roll use.
• Extremely Portable: The main unit weighs only approximately 0.5 kg. Its handheld design allows it to be easily carried to roll grinding machines or storage sites. A single measurement takes only 2–6 seconds, making it more than 20 times faster than traditional microhardness testers.
• No Spatial Limitations: Supports 360° measurement in any direction, without requiring vertical positioning like Shore testers. Particularly suitable for measuring special positions such as roll necks and chamfers.

Key Measurement Applications: What Can Sinowon Measure?

Leveraging high-precision sensors and intelligent algorithms, Sinowon ultrasonic hardness testers cover a comprehensive range of measurement scenarios in roll manufacturing and repair:

1. Base Material & Hardened Layer Depth Testing (Measuring Substrate Hardness)

For roll bodies made of forged steel, cast steel, and cast iron, the equipment directly measures substrate hardness on roll surfaces and end faces. Through multi-point testing, it verifies whether the heat treatment process controls roll body hardness within specified ranges (HS Shore scale or HRC Rockwell scale), ensuring excellent spalling resistance.

2. Surface Chrome & Copper Coating Hardness Measurement (Measuring Coating Hardness)

This is a core strength of Sinowon ultrasonic hardness testers. In the printing roll and anilox roll industries, the hardness of the chrome-plated surface layer directly determines wear resistance and service life. The Sinowon SU-320R anilox roll ultrasonic hardness tester is specifically optimized for this application, solving the problem where Leeb testers cannot accurately measure thin coatings (<15 µm). It effectively evaluates electroplating process quality and prevents printing waste caused by uneven coating wear.

3. Carburized/Nitrided Case Hardness Testing (Measuring Process Effectiveness)

For rolls requiring surface carburizing or nitriding (such as backup rolls), when measuring the hardness of extremely shallow surface layers, Sinowon ultrasonic hardness testers can be equipped with low-force probes (e.g., 1 kgf or 2 kgf) to accurately measure the surface hardness of carburized and nitrided cases. This helps companies precisely control chemical heat treatment processes and avoid early roll failure caused by "soft spots."

Problems Solved: Full-Process Support from Production to Quality Control

Introducing Sinowon ultrasonic hardness testers essentially establishes a digital hardness monitoring system for the entire roll lifecycle:

• Solving "Inaccurate Measurement"
  Using wireless Bluetooth technology, measurement data is stored in real time on the main unit and supports SPC statistical analysis. This effectively eliminates errors caused by manual reading, recording, and conversion.
• Solving "Incomplete Measurement"
  Whether for large backup rolls several meters in diameter or engraved rolls with deep groove structures, Sinowon’s compact probe (diameter 22 mm) can reach narrow areas, achieving dead-angle-free testing.
• Solving "High Costs"
  Enables on-site non-destructive measurement without the need for cutting and sampling. The portable design is ready for immediate use. With a Bluetooth printer, on-site test reports can be generated instantly, significantly reducing inspection costs and scrap rates.

Conclusion

In modern industry, which pursues zero defects and extreme efficiency, Sinowon ultrasonic hardness testers are not just "rulers" for measuring hardness. They are also the "sharp eyes" for roll manufacturing and user companies to control thermal spraying, electroplating, and heat treatment processes.

Choose Sinowon. Say goodbye to destructive sampling inspection and embrace a new era of full-scale, non-destructive, portable hardness testing for rolls.