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Improved Scan Plan Strategy with Compound S-Scan for Weld Inspection


In the nondestructive testing industry, it is important to obtain accurate results as quickly and efficiently as possible. There are many parameters to consider prior to inspecting a component, and the scan plan is an important part of this workflow. Having an efficient scan plan saves time and improves the quality of the inspection.

Improved Scan Plan Strategy with Compound S-Scan for Weld Inspection

Challenges when creating a scan plan

When creating a scan plan for weld inspection, the goal is to ensure that the entire area of interest (usually the weld volume and the heat affected zone) is covered by the range of ultrasonic beams that have been selected. Often, multiple groups of sectorial scans are needed to achieve this goal. Depending on the angle of the weld bevel, it can also be challenging to generate a beam that is perpendicular to the bevel. For example, if a weld has a 30-degree bevel, a 60-degree beam would create a theoretical 90-degree incident angle and, consequently, better detection for an indication occurring in the bevel wall. Increasing the number of probes or increasing the number of groups in a scan plan was often required to get successful coverage, however, adding either groups or probes often results in bulkier mechanical setups and decreased inspection speed.

Solution: compound S-scan

The compound S-scan is an inspection strategy consisting of a mix of linear and sectorial beams where the lower active aperture generates the lower angle beams and the higher active aperture generates the higher angle beams. With this setup, the compound S-scan generates a larger coverage area, replacing two standard sectorial scans (Figure 1).

A compound S-scan can either be created directly onboard the flaw detector in the OmniScan® software (version 4.4 or later) or created beforehand in NDT SetupBuilder (version 1.1r2 or later) and is usually optimized by using probes with a minimum of 32 elements.

Improved Scan Plan Strategy with Compound S-Scan for Weld Inspection
Improved Scan Plan Strategy with Compound S-Scan for Weld Inspection

Figure 1. Two groups of sectorial scans vs. one group using a compound S-scan.

Advantages of the compound S-scan technique

Since only one group is often sufficient to cover the entire weld, users gain multiple advantages.

First, using only one group means that only one calibration is required, enabling faster setup time. When using the compound S-scan, the range of angles required to get complete coverage of the weld is often reduced. Because the higher angles are the harder ones to calibrate due to beam divergence, the reduced range achieved with the compound S-scan makes calibration easier.

Second, since one group is usually sufficient to achieve full coverage, this reduces the number of focal laws for the same weld. Reducing the number of focal laws increases the scanning speed without compromising weld coverage. It also reduces analysis time, since users only have to review one group instead of two. The inspection screen is also less crowded, helping the inspector to view the data better (Figure 2).

Improved Scan Plan Strategy with Compound S-Scan for Weld Inspection
Improved Scan Plan Strategy with Compound S-Scan for Weld Inspection

Figure 2. Four groups crowded onto the screen vs. two groups during inspection or analysis.

A third advantage is that the index offset is shorter. Because the angles are generated at the back of the probe, users can position the probe closer to the weld than is usually possible. Being closer to the weld means that the coverage is primarily accomplished in the first leg, providing less sound attenuation in the part, more accurate sizing capabilities, and more confident results.

Furthermore, since the compound S-scan is distributing all the elements within the probe, a 16:XX configuration instrument, like the OmniScan® SX flaw detector, can still benefit from a 32 or 64 element probe and have increased coverage.


The compound S-scan can help improve the quality of a scan plan, as well as coverage, data file size, acquisition speed, and mechanical setup. Since this feature can now be used onboard your flaw detector with the latest version of OmniScan software (version 4.4 or later) and NDT SetupBuilder (version 1.1r2 or later), it is easier than ever to create a sectorial or linear scan.

Olympus IMS

OmniScan X3系列的每台探伤仪都是一款功能齐备的相控阵工具箱。其创新型全聚焦方式(TFM)和高级相控阵(PA)功能助力您充满信心地识别缺陷,其性能强大的软件功能和便捷的工作流程有助于提高您的检测效率。
轻便的单组Omniscan SX探伤仪装有一个方便用户阅读的8.4英寸(21.3厘米)触摸屏,可提供性价比很高的检测解决方案。OmniScan SX有两种型号:SX PA和SX UT。SX PA是一个16:64PR仪器,它与仅使用UT技术的SX UT一样,配备有一个用于脉冲回波、一发一收或TOFD(衍射时差)检测的常规UT通道。
这类专用于相控阵应用的探头的频率范围在0.5 MHz到18 MHz之间,其标准配置为16、32、64或128个晶片。特殊的探头可以最多装配几百个晶片。
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