I have a 100 watt fiber laser with a 100 and 200mm lense. I need to engrave a logo on a piece of stainless steel that will be in constant contact with salt water. Can anyone help me with what settings to use. I have tried with 200mm/s speed , 15% power, and 100KHz frequency. But barely shows up on the steel. I would like to have the logo be a dark black.