A complete bolt tensile test plan should be developed based on specific bolt types, performance requirements, and test objectives. The following table summarizes three types based on international standardsISO 898-1:2013You can choose and refer to the commonly used testing methods based on the specific situation of the bolt, such as whether it is a finished product or whether it needs to be tested for head strength.

Experimental equipment and core devices

tensile testing machineIt is the core equipment, and the selection needs to consider the bolt specifications (such as diameter) and strength grade to meet the requirements of maximum test force. ForM12The above high-strength bolts may require a maximum test force of1200kNOr a higher testing machine. Meanwhile, fixtures and devices are key to ensuring the effectiveness of the experiment.

-Wedge load test device: requires the use of a dedicated wedge pad with an angle of（4°6° or10The selection should be strictly based on the performance level of the bolt and the length of the unthreaded rod according to the standard.

-Finished tensile test fixture: A high hardness internal thread fixture or sleeve is required to clamp the threaded part of the bolt, and the effective thread engagement length should be at least1Double the diameter of the thread.

Experimental procedure and result determination

The standard test procedure mainly includes the following key steps:

1.Sample preparation: The sample should be a finished fastener product that has passed dimensional inspection.

2.Install the sample: Install it correctly according to the corresponding method (such as placing a wedge pad or screwing in the fixture).

3.Set parameters: Set the test rate. When determining the yield strength or specified plastic elongation strength, the rate should not exceed10 mm/minOther projects shall not exceed25 mm/min.

4.Conduct experiment: Start the testing machine, continuously load until the bolt breaks, and record the maximum tensile load during the process(Fm)Waiting for data.

5.Result calculation and judgment:

tensile strength Rm = Fm / AsAmong themAsThe nominal stress cross-sectional area.

The location of the fracture is an important criterion for judgment. For example, the finished product tensile test requires that the fracture should occur within the length of the unthreaded thread or on the unthreaded shaft; The wedge load test requires that there should be no fracture at the head.

Other key considerations and scenarios

-Specific industry standards: Some industries have stricter or special requirements. For example, the testing method standards for aerospace bolts are currently being developed, which will include more items such as high-temperature tensile testing, stress endurance testing, and stress corrosion testing.

-Special application scenario: For anchor systems such as foundation bolts, the pull-out test focuses more on evaluating their overall anchoring performance with the concrete matrix. The test method and judgment criteria are different from those for the bolt body mentioned above.

-Performance level interpretation: The performance level of bolts (such as8.8、10.9）Directly corresponding to its strength requirements. For example,10.9The standard value of tensile strength for grade bolts needs to reach1000 MPaThe yield strength needs to reach900 MPa.

Proposal formulation suggestions

Based on the above information, to develop a targeted experimental plan, we suggest that you follow the following approach:

1.Clarify the purpose of the experiment: to determine whether routine performance verification, head quality inspection, or precise yield performance measurement are required.

2.Confirm sample information: obtain key information such as the standard code, performance level, thread specifications, and whether the bolt is a finished product.

3.Determine standards and methods: Select the corresponding test method based on product standards and test objectives (refer to the table above).

4.Check equipment and fixtures: Ensure that the testing machine's range, accuracy, and specialized fixtures (wedge pads, threaded fixtures, etc.) meet the requirements of the selected standards.

5.Standardized testing and reporting: Strictly follow standard procedures and clearly record the testing methods, standards, key data, and compliance conclusions in the report.

If you can provide more specific bolt information (such as which type of equipment or engineering bolts are used and which specific standards need to be met), I can provide you with more targeted analysis.