How do machinability-improved stainless steels cut costs and increase production?

When measuring productivity and project cost savings it’s important to consider materials that are strong enough to withstand their intended use, yet flexible enough to be manufactured as a solid bar or hollow bar.

This is true for a wide variety of applications and sectors. From machined fittings and flanges for valves, pumps, heat exchangers and vessels, to tubular shafts for the chemical, petrochemical, fertilizer, pulp and paper and energy sectors.

It applies to machined parts from couplings to nuts and bolts used in a variety of industries including:

  • Automotive
  • Dairy industries
  • Foods and beverage
  • Marine
  • Oil and gas
  • Pharmaceuticals

It was also the intention behind the creation of Sandvik’s Sanmac® technology of machinability-improved stainless steels.

When selecting the correct stainless steel for your application there are seven key points to consider:

1. Economy

The aim for any component manufacturer is to maximize the value-added time and generate earnings for operations performed.

On average, a machine tool will utilize just 24% of available time during a calendar year. Around 36% of that time is spent setting up the machine tool and running trials to establish standard cutting data to suit material behavior.

Each material behaves differently during machining. Using stainless steels with tight tolerances and consistent chemical composition and microstructure can help quickly identify optimal cutting speeds to maximize production and minimize costs.

2. Productivity

Productivity depends on the material, the cutting tools and the machine. Selecting the correct material can enable higher cutting data and prolong tool life.

These five aspects can define the productivity of your machines:

  1. High cutting data

  2. Tool-life

  3. Energy consumption

  4. Chip breaking

  5. Surface finish

3. Material consistency

Minimizing downtime, maximizing utilization, greater standardization and reducing component costs are key to creating quality products at a lower cost. But if the raw material doesn’t have the same quality and consistency as the rest of the system, the whole machining operation will fail to achieve the expected cost-effectiveness. Most often, the quality of the raw material determines the efficiency of a machining operation.

Material consistency, where the same program and cutting data can be used for previously machined components, shortens run-in time and avoids additional trialing cuts.

4. Setup times

Short setup times enable higher machine utilization, quicker batch changes, less wastage of trial components and the reusability of cutting data programs. Using materials with tight tolerances and clean surfaces makes it easier for the operator to set the first cut correctly, with minimal stock.

5. Chip breaking

Machining stainless and duplex stainless steels is a challenge due to the high strength of the material. Chip formation is one of the most crucial aspects of any machining activity. Poorly managed chip breaking can harm the workpiece, the cutting tool, and be a major hazard for the operator.

Chip breaking is closely related to the microstructure, so ensuring the material has an even and optimized microstructure is essential.

6. Chemical composition

Materials that fulfill the same standards can still be different from each other. UNS and EN standards for chemical composition allow a wide tolerance. However, higher-end, tight tolerances improve the machinability, corrosion resistance and weldability of the chosen material.

7. Solid or hollow bar?

The decision on which to choose will be based on the fit to the final sizes required by the customer. Both have their strengths. However, where feasible for use, hollow bar means less material is wasted and dimensions close to the finished component size can lead to less machining time.

Use our bar converter to calculate the potential savings you could make between solid round bar and hollow bar.

Our Sanmac® range of machinability-improved bar and hollow bar stainless steels maintain the same quality from melt to melt, providing excellent machining properties for increased cutting speeds, reduced tool wear and shorter set-up times.

Whether you are close to the machining process or responsible for purchasing the material, learn how our Sanmac® technology can help you.

By Vinicius Martins, Sales Manager Latin America & Managing Director Mexico