Oil Field Equipment Drill Stabilizer/Drill Centralizer â?¢API standard oilfield stabilizers are manufactured from one solid bar of AISI 4145H modifed steel,usually have 3 blade or 4 blades.Professional heat-treatment process gurantees the mechanical strengths meet the requirments of API SPEC7-1.Hardness of 285-341HB can be assured bith 1'' beneath the outer suiface and 4 quadrant across the neck OD. â?¢Replaceable sleeve stabilizer consists of mandrel and sleeve.The function is the same as spiral integral blade stabilizer.It can suit to different hole size and increase working life by changing the different size sleeve.The sleeve is threaded on the mandrel, so the sleeve can be fasten to the mandrel tightly and changed easily.