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Materials Engineer Lab Intern (Year-Round)

Charter Manufacturing · Saukville, WI · Part time

Posted Sep 9, 2026 · We last checked this listing on Oct 6, 2026

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Likely interview questions for this role

Written from this job description, not a generic list. Each one notes what the interviewer is really checking.

About your past

Tell me about a lab class or project where you had to follow a procedure carefully.

What they are checking: Discipline with procedures, which matters for repeatable lab results.

Tell me about a time you made a mistake in a lab. How did you handle it?

What they are checking: Honesty and learning from mistakes, which matters when lab data drives decisions.

Why steel, and what do you want to learn here?

What they are checking: Genuine interest in materials and in the steel industry, which keeps interns engaged and growing.

What would you do

You get a hardness result that's way out of range for the grade. What do you do?

What they are checking: Whether they retest and check their method before reporting a result that could affect product decisions.

How will you manage 15 to 20 hours a week in the lab during the school year?

What they are checking: Reliability and scheduling for a year-round internship starting in January.

About the work

Walk me through how you'd prepare a steel sample for viewing under a microscope.

What they are checking: Familiarity with sectioning, mounting, polishing and etching, the daily work of this lab internship.

What's the difference between ferrite, pearlite and martensite, and how would each look under a microscope?

What they are checking: Basic microstructure knowledge needed to evaluate steel quality in the lab.

Have you done hardness testing? Which methods, and what can throw off a reading?

What they are checking: Hands-on testing knowledge and care about measurement accuracy.

How do you think a manufacturing step like rolling or cooling could create a defect you'd see in the lab?

What they are checking: Curiosity about how processes influence material performance, a core goal of the internship.

What safety habits do you follow when working with chemicals like etchants and with cutting equipment?

What they are checking: Lab safety awareness around acids, saws and grinding equipment.

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The full job description

As published by Charter Manufacturing.

Charter Manufacturing is a fourth-generation family-owned business where our will to grow drives us to do it better. Join the team and become part of our family! Charter Steel is a leading American supplier of carbon and alloy steel bar, rod and wire products, and the largest steel coil processor in North America. As a fully integrated steelmaker with locations in Ohio and Wisconsin, Charter Steel offers a full range of grade and size coiled products and vast technical service experience . Charter Steel is a member of the Charter Manufacturing   family of companies. About the Materials Engineer Lab Internship: Gain hands-on experience analyzing the microstructure and mechanical properties of steel while learning how manufacturing processes influence material performance. You'll use metallographic equipment, microscopes, hardness testing, and analysis software to evaluate steel quality and identify manufacturing defects. Program structure: • Schedule: Part-time (15-20 hours/week) during the academic year and full-time (40 hours/week) during the summer. • Location: Saukville, WI • Start Date: January 2027 • Duration: Year-round internship What we're looking for: • Enrollment in a four-year degree program in Materials Science & Engineering, Mechanical Engineering or a related field with current status of at least a Sophomore level. • Cumulative GPA of 2.75 or higher. • Proficient in Microsoft Office software: Excel, Word, and PowerPoint. • Strong verbal and written communication skills. • Strong interpersonal and relationship building skills. • Ability to succeed in a team environment. • Ability to handle multiple tasks. What you'll focus on: • Operate and assist in the maintenance of the TS lab metallographic equipment. • Document professional quality level images for use in Technical Service Reports to our internal and external customers. • Summarize findings to the TS Lab Group via email, Microsoft Teams, etc. • Take a lead role in the evaluation of Hercules and Niagara Lasalle accumulations claims. • Learn microstructures and mechanical properties of steel components. • Becoming familiar with the effects of various manufacturing processes on 'raw as-produced' steel. • Identifying manufacturing defects relating to the casting, hot rolling, processing, and forming of steel components. • Experience using metallographic equipment, macro and microscopes, automated analysis software, Rockwell and Microhardness testing. What Sets Our Internship Program Apart: Work on meaningful projects while receiving mentorship, professional development, and networking opportunities that help launch your career. Our paid internship program also includes signature experiences like Charter's Intern Kickoff Day, volunteer opportunities, professional development workshops, and the Intern Summer Showcase. #LI-AF1 #LI-Onsite #CharterSteel Internship positions are not benefits-eligible.

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