shared the results of a detailed study conducted by the company comparing Inconel 625 solid bars with the new Sanicro 60 hollow bars.
Competitive grade Inconel 625 (UNS number N06625) is a nickel-based superalloy (heat resistant superalloy) that has been used in the marine, nuclear and other industries since its original development in the 1960s due to its high strength properties and resistance to high temperatures. temperatures. It has increased protection against corrosion and oxidation.
The new Challenger is a hollow-rod variant of the Sanicro 60 (also known as Alloy 625). Sandvik’s new hollow core is designed to provide better performance in certain areas occupied by Inconel 625, made from a high strength nickel-chromium alloy that can withstand extremely high temperatures in chlorine-containing environments. Resistant to intergranular corrosion and stress corrosion, has a Pitting Resistance Equivalency (PRE) greater than 48.
The aim of the study was to comprehensively evaluate and compare the machinability of Sanicro 60 (diameter = 72 mm) with Inconel 625 (diameter = 77 mm). The evaluation criteria are tool life, surface quality and chip control. What will stand out: the new hollow bar recipe or the traditional whole bar?
The evaluation program at Sandvik Coromant in Milan, Italy consists of three parts: turning, drilling and tapping.
The MCM Horizontal Machining Center (HMC) is used for drilling and tapping tests. Turning operations will be performed on a Mazak Integrex Mach 2 using Capto holders with internal coolant.
Tool life was evaluated by evaluating tool wear at cutting speeds ranging from 60 to 125 m/min using an S05F alloy grade suitable for semi-finishing and roughing. To measure the performance of each test, material removal per cutting speed was measured by three main criteria:
As another measure of machinability, chip formation is evaluated and monitored. The testers evaluated chip generation for inserts of various geometries (Mazak Integrex 2 used with PCLNL holder and CNMG120412SM S05F turning insert) at a cutting speed of 65 m/min.
The quality of the surface is judged according to strict criteria: the surface roughness of the workpiece should not exceed Ra = 3.2 µm, Rz = 20 µm. They should also be free from vibration, wear, or built-up edges (BUE – material buildup on cutting tools).
Drilling tests were carried out by cutting several discs from the same 60 mm rod that was used for the turning experiments. The machined hole was drilled parallel to the axis of the rod for 5 minutes and the wear of the back surface of the tool was periodically recorded.
The threading test evaluates the suitability of hollow Sanicro 60 and solid Inconel 625 for this important process. All holes created in the previous drilling experiments were used and cut with a Coromant M6x1 thread tap. Six were loaded into an MCM horizontal machining center to experiment with different threading options and ensure that they remain rigid throughout the threading cycle. After threading, measure the diameter of the resulting hole with a caliper.
The test results were unequivocal: Sanicro 60 hollow bars outperformed solid Inconel 625 with longer life and better surface finish. It also matched solid bars in chip forming, drilling, tapping and tapping and performed equally well in these tests.
The service life of hollow bars at higher speeds is significantly longer than solid bars and more than three times longer than solid bars at a cutting speed of 140 m/min. At this higher speed, the solid bar lasted only 5 minutes, while the hollow bar had a tool life of 16 minutes.
Sanicro 60 tool life remained more stable as the cutting speed increased, and as the speed increased from 70 times to 140 m/min, tool life decreased by only 39%. This is 86% shorter tool life than Inconel 625 for the same change in speed.
The surface of a Sanicro 60 hollow rod blank is much smoother than that of a solid Inconel 625 rod blank. This is both objective (surface roughness does not exceed Ra = 3.2 µm, Rz = 20 µm), and is measured by visual edge, traces of vibration or damage to the surface due to the formation of chips.
The Sanicro 60 hollow shank performed the same as the older Inconel 625 solid shank in the threading test and showed similar results in terms of flank wear and relatively low chip formation after drilling.
The findings strongly support that hollow rods are an improved alternative to solid rods. Tool life is three times longer than the competition at high cutting speeds. The Sanicro 60 not only lasts longer, it’s also more efficient, working harder and faster while maintaining reliability.
With the advent of a competitive global marketplace that is pushing machine operators to take a long-term view of their material investments, Sanicro 60′s ability to reduce wear on machining tools is a must for those looking to increase margins and more competitive product prices. it means a lot.
Not only will the machine last longer and changeovers be reduced, but using a hollow core can bypass the entire machining process, eliminating the need for a center hole, potentially saving a lot of time and money.