Abstract: The invention relates to a perforating gun used for hydraulic fracturing applications in a wellbore and has an outer tube having several recesses of a second kind. The recesses of a second kind are configured to absorb shock waves from a shape charge in the perforating gun to reduce the numbers of cracks that form on the perforating pun. In some embodiments, the recesses of a second kind have a variety of shapes and sizes to aid in the absorption of shock waves.

Abstract: In a method for the production of a seamless, multilayered tubular product, a further layer is applied through hardfacing on a base layer of a round or polygonal block, with the further layer made of a metallic material which is different than a metallic material of the base layer. The round or polygonal block with hardfaced further layer is hot formed to produce a tubular product with reduced wall thickness and outer perimeter in one or more stages. A diffusion layer is established between the base layer and the further layer through heat treatment before hot forming and/or after hot forming, thereby producing a thickness of the diffusion layer of at least 5 ?m with the proviso that the thickness of the diffusion layer is 0.1% to 50% of a thickness of the further layer, with the thickness of the further layer being equal to or greater than 100 ?m.