Device and method for protecting the rock drilling machine from corrosion

1. An arrangement for a rock drilling machine for percussive drilling, the arrangement comprising:

a casing part comprising a base material and at least one end plane, wherein the end plane comprises a first region and a second region, wherein the first region comprises at least one part of an outer contour of the end plane at least partially surrounding the second region and having a surface that is coplanar with the end plane, and wherein the first region comprises a material that resists corrosion, the material comprising stainless steel, an alloy or ceramic.

2. The arrangement according to claim 1 , wherein the first region comprises a complete outer contour of the end plane.

3. The arrangement according to claim 1 , wherein the second region comprises a material that resists corrosion.

4. The arrangement according to claim 1 , wherein the second region comprises the base material.

5. The arrangement according to claim 1 , further comprising:

at least one groove in the end plane, the at least one groove configured to permit lubricating oil and air mixture to pass from an interior of the casing part to an exterior of the casing part.

6. The arrangement according to claim 1 , wherein the material that resists corrosion overlies the base material.

7. A joint in a hammer rock drilling machine, comprising:

two casing parts each comprising a base material and at least one end plane, wherein the end plane comprises a first region and a second region, wherein the first region comprises at least one part of an outer contour of the end plane at least partially surrounding the second region and having a surface that is coplanar with the end plane, and wherein the first region comprises a material that resists corrosion, the material comprising stainless steel, an alloy or ceramic,

wherein the first regions of the casing parts that comprise material that resists corrosion have a same shape and are arranged in sealing contact in a dividing plane.

8. The joint according to claim 7 , wherein at least one of the casing parts further comprises at least one groove in the end plane, the at least one groove configured to permit lubricating oil and air mixture to pass from an interior of the casing part to an exterior of the casing part.

9. The joint according to claim 7 , wherein the material that resists corrosion overlies the base material.

10. A rock drilling machine arranged for percussive drilling, comprising:

at least one joint comprising two casing parts each comprising a base material and at least one end plane, wherein the end plane comprises a first region and a second region, wherein the first region comprises at least one part of an outer contour of the end plane at least partially surrounding the second region and having a surface that is coplanar with the end plane, and wherein the first region comprises a material that resists corrosion, the material comprising stainless steel, an alloy or ceramic, wherein the first regions of the casing parts that comprise material that resists corrosion have a same shape and are arranged in sealing contact in a dividing plane, and wherein the joint is radially positioned such that the relevant first regions of material that resists corrosion cover each other and are arranged in a region of the drilling machine at which the risk of corrosion is greatest.

11. The rock drilling machine according to claim 10 , wherein at least one of the casing parts further comprises at least one groove in the end plane, the at least one groove configured to permit lubricating oil and air mixture to pass from an interior of the casing part to an exterior of the casing part.

12. The rock drilling machine according to claim 10 , wherein the material that resists corrosion overlies the base material.

13. A method to protect from corrosion a rock drilling machine for percussive drilling, comprising a number of joints with a plurality of casing parts each one of which comprising a base material and at least one end plane, where the end plane comprises a first and a second region, where the first region comprises at least one part of the outer contour of the end plane at least partially surrounding the second region and having a surface that is coplanar with the end plane, and wherein the first region comprises a material that resists corrosion, the material comprising stainless steel, an alloy or ceramic, the method comprising:

assembling a rock drilling machine by joining a plurality of casing parts with first regions that are similarly formed in pairs, such that the first regions in a number of joints cover each other in a manner that produces a seal, and

pressurizing the joints in the rock drilling machine during operation by an oil and air mixture whereby the first regions in each joint seal and prevent the oil and air mixture from passing out through the first regions, and at the same time seal and prevent corrosive water in surroundings of the rock drilling machine from penetrating the component dividing planes, whereby the oil and air mixture lubricates second regions that are part of each dividing plane.

14. The method according to claim 13 , wherein the material that resists corrosion overlies the base material.

15. The method according to claim 13 , wherein the oil and air mixture is caused to pass out through at one groove in at least one of the end planes to lubricate the joints.