How to rapidly measure wall thickness of an operating high-temperature pipeline without shutdown or cooling down? How to conduct wall thickness inspection on storage tanks with thick anti-corrosion coatings without damaging the coating layer?

For petrochemical, pressure vessel, shipbuilding and steel structure industries, equipment wall thickness is a core indicator for safe operation. However, traditional thickness testing methods struggle to handle workpieces under high temperatures, with intact coatings or rusted surfaces. The launch of EMAT thickness pens solves such testing bottlenecks. Featuring non-contact operation, couplant-free measurement and no surface grinding required, they have become the preferred non-destructive thickness testing equipment for industrial scenarios.

Working Principle of EMAT Thickness Pen

The electromagnetic acoustic transducer (EMAT) thickness pen leverages EMAT technology. Combined with static magnetic field supplied by permanent magnets, high-frequency magnetic fields generated by coils directly induce ultrasonic waves inside metallic materials. Ultrasonic waves propagate through the material and reflect off the bottom surface, with the probe receiving echo signals. The equipment calculates wall thickness by measuring the round-trip propagation time of ultrasonic waves and the material’s acoustic velocity.

This fundamental working principle eliminates the reliance on couplants required by conventional ultrasonic thickness gauges, enabling simple and reliable measurements on rough surfaces, coated parts and high-temperature workpieces.

Three Models of EMAT Thickness Pens: Core Technical Specifications

Drawing on years of accumulated non-destructive testing expertise, Zheda Jingyi independently developed three EMAT thickness pens: EMTP10, EMTP20S and EMTP20. The product portfolio covers ambient to ultra-high temperature applications to meet diverse industrial demands.

Model Selection Guide

• EMTP10: For ambient temperature inspection

• EMTP20S: For on-line thickness measurement up to 800℃

• EMTP20: Supports both high-temperature testing and ultra-thick workpiece measurement

Core Technical Parameters

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Four Core Advantages for More Efficient & Precise Thickness Inspection

Technical parameters lay the foundation, while outstanding performance delivers real value. Below are the four core strengths of Zheda Jingyi EMAT series thickness pens:

1. Easy Operation, Dramatically Improved Inspection Efficiency

• Couplant-free measurement: Unlike conventional ultrasonic thickness gauges, EMTP series requires no couplant coating. Users can start measurement immediately after power-on, greatly boosting inspection efficiency and cutting consumable costs.

• No grinding or coating removal required: The maximum lift-off distance between probe and workpiece reaches 4mm, eliminating the need for tight surface contact. For uneven surfaces and coated components, pre-grinding is unnecessary, simplifying workflows and fully protecting the original surface structure of workpieces.

2. 0.01mm Ultra-High Precision, Compatible with Multiple Metals

Precision measurement is critical for industrial corrosion monitoring and wall thickness evaluation. Adopting advanced signal processing algorithms and high-sensitivity probe design, the EMTP series delivers ultra-precise thickness readings:

• Measurement resolution up to 0.01mm

• Measurement error as low as ±0.02mm for thickness below 10mm, meeting strict industrial corrosion monitoring standards

• Compatible with carbon steel, cast steel, alloy steel, stainless steel, copper, aluminum alloy, titanium alloy and other metallic materials

• Supports pipes with minimum diameter of 8mm and maximum measurable thickness of 300mm, catering to complex structural component inspection

3. Adaptable to Harsh Working Conditions, Stable Performance at High Temperatures

The three EMTP models are categorized into ambient and high-temperature types to fully cover wide temperature ranges:

• Ambient probe: -40℃ ~ 120℃ workpiece temperature range

• High-temperature probe: -40℃ ~ 800℃ workpiece temperature range

Under high-temperature testing mode, the instrument automatically compensates measurement deviations caused by temperature fluctuations. Continuous on-line inspection can be performed without equipment shutdown or workpiece cooling.

4. Integrated Pen-Style Design, Lightweight & Intelligent for Easy Portability

Optimized for field inspection experience, the thickness pens prioritize portability and intelligence for on-demand testing anywhere:

• Ultra-lightweight: Only over 200 grams, single-hand operation for inspection on high-altitude steel structures, ship bulkheads, tank tops and complex pipe racks

• Extended battery life: Large-capacity lithium battery delivers up to 5 hours of continuous operation with auto-sleep function for long-term patrol inspection

• Intelligent display & data transmission: Built-in high-definition OLED screen displays real-time thickness values and echo waveforms to help inspectors quickly judge measurement validity and improve reliability. EMTP20 series supports WiFi wireless connection with mobile terminals for on-site data viewing and analysis.

Comparative Analysis: EMAT Thickness Pen vs Traditional Testing Methods

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Typical Application Scenarios & Industrial Solutions

With outstanding environmental adaptability and high precision, Zheda Jingyi EMAT thickness pens are widely deployed across petrochemical pipelines, pressure vessels, storage tanks, shipbuilding, wind power, steel structures, metallurgy, construction and other industries.

Energy & Chemical Industry

Wall thickness and corrosion inspection for oil & gas transmission pipelines, chemical reaction storage tanks and pressure vessels; non-stop on-line monitoring of high-temperature pipelines.

Shipbuilding & Steel Structure Industry

Thickness measurement of ship plates and pipes; wall thickness sampling inspection and corrosion assessment for building steel structures and large steel frames.

General Manufacturing

Factory thickness quality inspection for various metal sheets, pipes and mechanical parts; rapid screening of rough-surface and coated workpieces.

Industrial thickness testing is evolving from basic "capable measurement" toward fast, precise and on-line inspection.

Centered on proprietary EMAT technology, Zheda Jingyi EMTP series thickness pens break the dependency of traditional testing tools on couplants and surface pre-treatment, enabling efficient, accurate measurements under complex working conditions including high temperatures, intact coatings and rough surfaces.

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