The thickness tolerance of marine steel plate for hull structure has been modified in the new unified requirements. The main changes are as follows:
1. Although the negative thickness deviation of marine steel plate for hull structure is still 0.3mm, the concept of average thickness is introduced, and the average thickness measured by marine steel plate shall not be less than the nominal thickness of steel plate is stipulated. Positive tolerance shall be implemented according to relevant national standards.
2. The thickness measurement method is stipulated, that is, the thickness of the steel plate can be measured by automatic or manual measurement method. At least two lines are selected according to the required measurement position, and at least three measuring points are selected for each line. The mean thickness is the arithmetic mean of the measured results.
3. If steel mill is rolling marine steel plate for hull structure according to positive tolerance control, it is not necessary to measure the thickness and calculate the average thickness of steel plate according to article 2.
