Fillet Weld Gage to check dimension of welds

Measuring Fillet Weld Leg and Throat | The Best Way

In fillet weld leg size and throat inspection by Matthew BehlenLeave a Comment

Introduction

Always gauge fillet weld characteristics. They are one of the most common types of welds used in construction and manufacturing. They are used to join two pieces of metal together at a right angle. The size of the fillet weld leg and the throat are important factors in determining the strength of the weld.

The leg size is the width of the weld at its widest point. The throat is the shortest distance between the two surfaces being joined. The ideal size for the fillet weld leg and throat will vary depending on the thickness of the metal being welded and the application.

In this article, we will discuss the proper size for fillet weld legs and throats, how to measure them, and the consequences of incorrectly sized fillet welds. We will also provide tips for proper fillet weld leg size and throat inspection.

Fillet Weld Leg Size

The leg size of a fillet weld is the distance from the toe of the weld to the root of the weld. The leg size is important because it affects the strength of the weld.

The minimum leg size for a fillet weld is specified in the applicable welding code. For example, the American Welding Society (AWS) D1.1 code specifies that the minimum leg size for a fillet weld is 1/16 inch.

The leg size of a fillet weld can be measured using a fillet weld gage or a bridge cam gauge.

Fillet Weld Throat Inspection

The throat of a fillet weld is the shortest distance between the root face and the face of the weld. It is measured perpendicular to the direction of welding. The throat inspection is performed to ensure that the weld meets the required throat size.

The throat inspection can be performed visually or with a measuring tool. Visual inspection is the simplest method, but it is not always accurate. A measuring tool, such as a throat gage, can be used to provide a more accurate measurement. A quick pass fail gage is the “W” looking side of the appropriate sized fillet weld gauge.  If the center of the “W” touches and the inspector cannot touch both outside edges, it is typically sufficient.

The throat inspection is important because it ensures that the weld is strong enough to withstand the forces that will be applied to it. If the throat is too small, the weld will be weaker and more likely to fail.

The following are the steps involved in performing a throat inspection:

  1. Clean the weld surface to remove any dirt, rust, or slag.
  2. Identify the root face of the weld. The root face is the surface of the weld that was in contact with the base metal during welding.
  3. Measure the distance between the root face and the face of the weld. This is the throat size.

It is important to ensure that the throat of a fillet weld is within the specified limits to ensure that the weld is strong enough to meet the design requirements.  Design requirements for accurate inspections also require an alignment and fit-up inspection to ensure accuracy.

Fillet Weld Gage to check dimension of welds

Fillet Weld Gage to check dimension of welds for AWS D1.1.

Consequences of Incorrectly Sized Fillet Welds

Incorrectly sized fillet welds can have a number of consequences, including:

  • Reduced strength of the weld
  • Increased stress concentration at the weld
  • Increased risk of cracking
  • Reduced fatigue life of the weld

It is important to ensure that fillet welds are properly sized in order to avoid these consequences.

How to Correct Undersized or Oversized Fillet Welds

If a fillet weld is found to be incorrectly sized, it can be corrected by either adding or removing material from the weld. The following steps can be used to correct an incorrectly sized fillet weld:

  1. Determine the correct size of the fillet weld. This can be done by referring to the welding code or standard that applies to the project.
  2. Measure the size of the existing fillet weld. This can be done using a micrometer or other measuring tool.
  3. Calculate the amount of material that needs to be added or removed to correct the size of the fillet weld.
  4. Add or remove material from the weld until it meets the correct size.
  5. Inspect the weld to ensure that it meets the required quality standards.

Repairing an incorrectly sized fillet weld can be a difficult and time-consuming process. If the weld is not corrected properly, it could lead to problems with the strength and integrity of the joint. Therefore, it is important to carefully follow the steps above to ensure that the weld is corrected correctly.

Tips for Proper Fillet Weld Leg Size and Throat Inspection

Here are some tips for ensuring proper fillet weld leg size and throat inspection:

  • Use the correct welding procedure and materials.
  • Follow the engineer’s instructions for the use of correct process welding equipment and consumables.
  • Inspect the welds visually for any defects.
  • Use a fillet measuring device to check the weld leg size and throat.
  • Record the results of your inspection in a logbook.

By following these tips, you can help ensure that your fillet welds are properly sized and inspected, and that they meet the required specifications.  It is always a good idea to have an AWS CWI perform the inspections if you’re unsure.

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