Compatible Equipment Type: Excavator. Material 50Mn, through hardened HRC 25-28, CASE hardened HRC52-56, hardened thickness 5-8mm. Yield strength? 0.2 (MPa):? 310. Roller, 45# carbon steel or 40Cr, quenched HRC25-30, surface quenched HRC52-58, hardened to a depth of 2-3mm. Bolt, grade 12.9, HRC45-52. This bottom roller is a durable undercarriage replacement part for your excavator. Our rollers utilize special high strength-hardened steel and quality seal groups that provide excellent lubricating oil retention. Sealed bearings stop dirt, mud, and grime from penetrating inner components. It was designed and manufactured to exact OEM specifications using a high-quality, high-strength steel. It will provide long-lasting and dependable performance even if you operate in the most extreme conditions. Please make sure it will fit your machine before purchasing it. If you are not 100% sure this is what you need, please find out your engine model, series number and contact our Customer-service. Communication is the best way to solve the problem. If you have any problems after you. Caribbean, Europe, Middle East, North America, Oceania, Southeast Asia, South America, PR, PO Box. 60 Days Free Return, please notify us within 60 days after you’ve received your product. All accessories & hardware. It covers functionality problems that occur with the auto part as a result of manufacturing. It does not cover damage caused by improper installation; by accidents or damage sustained after installation; or by negligence in maintaining the part after installation. We will try our best to reply all e-mails within 24 hours, there might be some delay during weekends and holidays. Please leave us all positive feedbacks and all “5 Star” ratings, we will do the same to you. Please do not leave us any negative or neutral feedbacks before contacting us to solve the problem. It won’t help you solve the problem any faster by leaving negative feedbacks, only by contacting our professional customer suppport can help you solve the problems.