Method for the production of a seamless, multilayered tubular product, and round or polygonal block for use in this method

A method for the production of a seamless, multilayered tubular product, comprising:

• hardfacing a further layer on a base layer of a round or polygonal block, with the further layer being made of a metallic material which is different than a metallic material of the base layer;
• hot forming the round or polygonal block with hardfaced further layer to produce a tubular product with reduced wall thickness and outer perimeter in one or more stages;
• and
• establishing a diffusion layer between the base layer and the further layer through heat treatment at least in one of the phases selected from the group consisting of before hot forming and after hot forming, thereby producing a thickness of the diffusion layer of at least 5 μm on the tubular product, with the proviso that the thickness of the diffusion layer is 0.1% to 50% of a thickness of the further layer on the tubular product, with the thickness of the further layer being equal to or greater than 100 μm.