Weld Engineer Jobs in California (NOW HIRING)

At Antares, our long-term mission is to make clean energy abundant from Earth to the Asteroid Belt. We’re fueled by the belief that advanced nuclear energy can strengthen our military, solve the climate crisis, elevate global living standards, and expand humanity's presence in outer space. To achieve our mission, we’re building mass-producible, inherently safe, deployable microreactors that can be used terrestrially, underwater, and in space.

Formed in 2023, the Antares team hails from SpaceX, The White House, MIT, Rigetti Computing, The Air Force, General Atomics, Relativity Space, Ursa Major, and National Laboratories like Los Alamos, Idaho, and Oak Ridge. Antares has raised over $130M in venture capital from top-tier investors and has over $13M in government funding.

As a Welding Engineer II at Antares, you will support the development, qualification, and production of welded hardware for our reactor systems. You will own welding processes from early design and material selection through procedure development, qualification, manufacturing, inspection, and final acceptance. This role requires a strong understanding of welding metallurgy, fabrication processes, and weld quality—particularly for stainless steels, nickel-based superalloys, and other materials used in high-temperature and demanding environments. You will work closely with design, materials, manufacturing, quality, and external suppliers to ensure welded assemblies meet performance, reliability, and regulatory requirements.

The ideal candidate combines sound welding fundamentals with a hands-on, practical approach to manufacturing. You should be comfortable working directly with welders and technicians, troubleshooting issues on the floor, and developing scalable processes for first-of-a-kind reactor hardware.

• Develop, qualify, and maintain welding procedures, including Welding Procedure Specifications (WPS), Procedure Qualification Records (PQR), and welder performance qualifications.

• Select appropriate welding processes, filler metals, joint designs, shielding methods, and process parameters based on material and component requirements.

• Provide design-for-welding guidance, including recommendations related to joint accessibility, distortion, residual stress, inspection, and manufacturability.

• Support welded hardware from prototype development through production, inspection, testing, and final acceptance.

• Work directly with welders, technicians, and suppliers to establish repeatable, high-quality fabrication processes.

• Create manufacturing work instructions, process controls, weld maps, inspection criteria, and technical specifications.

• Develop and execute weld qualification plans, including destructive and nondestructive testing.

• Review weld documentation, inspection results, material certifications, and supplier records for compliance with engineering requirements.

• Lead root-cause investigations for weld defects, distortion, cracking, leakage, and other fabrication nonconformances.

• Develop repair and rework procedures and provide technical disposition of welding-related nonconformances.

• Interface with design, materials, analysis, manufacturing, quality, and test engineers to ensure welded assemblies satisfy structural, thermal, pressure, and lifetime requirements.

• Support the selection, qualification, and technical oversight of welding suppliers and outside fabrication partners.

• Promote a strong culture of safety, quality, documentation, and continuous process improvement.

• Bachelor’s degree in Welding Engineering, Materials Science and Engineering, Mechanical Engineering, or a related technical field.

• 2+ years of professional experience in welding engineering, joining processes, or welded hardware manufacturing.

• Working knowledge of common fusion welding processes, such as GTAW, GMAW, PAW, laser welding, or electron beam welding.

• Experience developing or supporting welding procedures and welder qualifications.

• Understanding of welding metallurgy, heat-affected zones, solidification, distortion, residual stress, and common weld defects.

• Experience interpreting engineering drawings, weld symbols, material specifications, and inspection requirements.

• Familiarity with destructive testing and nondestructive examination methods used to evaluate weld quality.

• Ability to work hands-on with production personnel and independently resolve manufacturing challenges.

• 3+ years of welding engineering experience in aerospace, nuclear, pressure vessel, power generation, defense, or another highly regulated industry.

• Experience welding stainless steels, nickel-based superalloys, refractory metals, or dissimilar-metal combinations.

• Knowledge of applicable welding and fabrication codes, including ASME Section IX, ASME Boiler and Pressure Vessel Code, AWS D17.1, AWS D1.1, or equivalent standards.

• Experience with pressure-boundary, high-temperature, vacuum, or leak-tight welded assemblies.

• Familiarity with advanced welding processes, including automated orbital GTAW, laser beam welding, electron beam welding, resistance welding, or add i tive repair.

• Experience developing weld fixtures, tooling, purge systems, and methods for controlling distortion and heat input.

• Experience with weld inspection methods such as visual, dye penetrant, radiographic, ultrasonic, leak, or metallographic examination.

• Familiarity with post-weld heat treatment, stress relief, cleaning, passivation, and contamination control.

• Experience conducting weld failure investigations using metallography, microscopy, hardness testing, or mechanical testing.

• Certified Welding Inspector (CWI), International Welding Engineer (IWE), or similar professional qualification.

• Ability to work long hours and weekends as necessary to support critical milestones

• The Antares HQ is located in Torrance, CA in a 322,000 square foot, brand new facility featuring large open spaces for team collaboration, R&D, and production, as well as easy access to the 405, 105, and 110 freeways. Our HQ is in the heart of Los Angeles' vibrant emerging tech ecosystem alongside many other high growth startups and enterprises.

At Antares, we like to specifically tie each role to our founding document’s set of values–here are the top five cultural values we think you should believe at your core to be successful:

• Think in Systems - Energy and Defense are complex ecosystems with numerous stakeholders with competing priorities, conflicting policies, perverse incentives, and emergent and path-dependent properties. First principles thinking alone is insufficient. Think probabilistically and then take action. “If you want to be certain, then you are apt to be obsolete.” Over-optimizing the components often degrades the system

• Obsess over the End User - The customer and end user are often not the same. We will never build globally competitive commercial products if we lose sight of our end users and their entire interaction with the product life cycle

• Be Unconstrained by Convention - Our only limits are the laws of physics. Many, even experts, will say what we are working on is impossible. They said the same about SpaceX reusing rockets. Generationally impactful companies, by definition, must accomplish the seemingly impossible. If it were easy, it would have already been done. Never shy away from a solution because it has never been tried before, and never choose to do something because that's “how it's always been done”

• Go Where the Work I’s - Never miss a chance to meet a customer, user, or stakeholder face to face, even if that means hopping on a plane. If you can’t make it, find a teammate who can channel your intentions and go in your place. Deep work can be done from anywhere, but we believe teams are built in person, and aim to maximize our time together

• Operate in the Grey - Embrace nuance in pursuit of truth. Question every fundamental assumption

Antares is an Equal Opportunity Employer. Employment decisions are based solely on merit, competence, and qualifications, without regard to race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability, or any other legally protected status.

To conform to U.S. Government export regulations, applicant must be a (i) U.S. citizen or national, (ii) U.S. lawful, permanent resident (aka green card holder), (iii) Refugee under 8 U.S.C. § 1157, or (iv) Asylee under 8 U.S.C. § 1158, or be eligible to obtain the required authorizations from the U.S. Department of State. Learn more about the ITAR here.