Naohiro YOSHIDA

Residual Axial Force and Slip Strength of Friction Bolt Joint by Using Laser Beam Cutting

Eiji IWASAKI,Masatugu NAGAI


In present Specifications for Highway Bridges, automatic gas cutting is known as a method to carry out cutting
main member in principle. On the other hand, the laser beam cutting is selected as the best method to
ensure the quality of steel member. Moreover, the hole opening is done by using together about drill or
drill and reamer.

On the other hand, there are a lot of construction companies that introduce the laser beam cutting with
cutting ability for thickness of plate to exceed 20mm recently. As for the method of laser cutting has
some functions of cutting process with high accuracy, little distortion, outline cutting but also the
function of hole opening. However, it is necessary to clarify the influence of joint function caused by
dissolved notch and hardening that occurs in surrounding of hole by local heat input with laser. In this
study, the application of the laser beam cutting to friction joint of high power bolt was discussed by
paying attention to Residual axial force and Slip strength.

The conclusions of this study can be summarized as follows:
1) As a result of the Residual axial force Test, there is no difference point between laser beam cutting
and drill processingD
2) All the results of Slip strength Test with all kinds of steel, because the average slipping
coefficient by the laser beam cutting obtains an almost similar value by drill processing, it is understood
that the laser beam cutting has the same capability as drill processing.
3) It is understood that there is a little influence of the heat input hardening by laser.
4) From above results, as for Residual axial force and Slip strength of Friction Bolt Joint, bolt
hole of the laser beam cutting has the similar degree as drill processing.