Magnesium Machining and Fabrication in Meridian, MS — AZ31B, AZ91D, and WE43 Sourcing

NAS Meridian operates T-6 Texan II trainers and historically supported a range of fixed-wing platforms. Every airframe in active training use has structural brackets, instrument housings, gearbox cases, and access panels where the alloy choice is driven by a strict weight budget. AZ31B sheet — typically supplied in H24 temper at 0.040 to 0.250 inch thickness — is the workhorse for formed panels and non-structural enclosures. Its tensile strength of roughly 290 MPa and yield around 220 MPa are adequate for these applications, and the alloy machines cleanly at surface speeds well above those used for steel, keeping cycle times low. Further into the supply chain, Meridian's heavy-equipment fabricators occasionally specify magnesium for portable ground-support tooling and lightweight jig fixtures. A magnesium tooling plate weighs about one-quarter as much as a comparable steel plate, reducing operator fatigue on the shop floor and simplifying overhead crane load calculations. Local shops familiar with military material traceability can extend those same documentation practices to commercial heavy-equipment customers who need full material certs and first-article inspection reports. The regional industrial character also includes electronics manufacturing, historically represented by Peavey Electronics' Meridian presence. Magnesium die castings — primarily AZ91D, which offers a superior combination of castability and corrosion resistance — appear in audio equipment chassis and enclosures where stiffness-to-weight ratio matters more than ultimate strength. AZ91D castings can hold dimensional tolerances of plus or minus 0.005 inch in the as-cast condition on critical surfaces, tightening further with secondary CNC operations.

AZ31B is the entry-level wrought alloy — available as rolled sheet, plate, and extruded bar — and it dominates applications that require forming, bending, or welding. Meridian fabricators can TIG-weld AZ31B using AZ61A filler rod with proper preheating to 300-400 degrees Fahrenheit, avoiding the hot-tearing risks that trip up shops unfamiliar with magnesium. Post-weld stress relief at 500 degrees Fahrenheit for one hour is standard practice on assemblies that will see cyclic loading. Corrosion protection via chemical conversion coating (MIL-M-3171 Type VI) or anodizing adds a critical barrier in the humid Mississippi Gulf Coast climate that pushes inland to Meridian. AZ91D is a pressure die-casting alloy with aluminum content near 9 percent and zinc around 0.7 percent, giving it better room-temperature strength than AZ31B — tensile strength reaches approximately 230 MPa, yield around 150 MPa — combined with excellent fluidity for thin-wall sections down to 0.060 inch. Defense brackets, electronics housings, and instrument panel components all benefit from AZ91D's castability. Local foundry partners within the east-central Mississippi region can supply net-shape or near-net-shape castings, reducing the machining burden on Meridian CNC shops. WE43 represents the high-performance tier: a rare-earth-containing alloy (yttrium plus mixed rare earths) with elevated temperature stability up to 572 degrees Fahrenheit and superior corrosion resistance compared to conventional AZ alloys. Aerospace turbine-adjacent housings, actuator bodies, and structural nodes on next-generation platforms drive WE43 demand. The alloy commands a significant price premium — roughly three to five times the cost per pound of AZ31B — so it is reserved for applications where weight and elevated-temperature performance cannot be traded away. Meridian shops with AS9100 certification are equipped to handle the traceability documentation WE43 programs require.

Magnesium is the most machinable structural metal in common production use. Surface speeds of 1,000 to 5,000 surface feet per minute are achievable with carbide tooling, and the low cutting forces mean small CNC mills can hold tolerances of plus or minus 0.001 inch on magnesium that would require heavier machines for steel. The tradeoff is fire risk: magnesium chips and fines ignite at relatively low temperatures, and a chip fire fed by coolant can escalate quickly. Meridian shops processing magnesium must use dry machining or mineral-oil-based coolants — never water-based emulsions — and collect chips frequently with Class D fire extinguishers staged nearby. Welding-fabrication houses in Meridian that already handle aluminum structures for defense customers will find the transition to magnesium manageable with proper process qualification. The key differences are tighter shielding gas flow (pure argon, 15-20 CFH), lower heat input to avoid liquation cracking, and mandatory surface cleaning to remove oxide and flux residue. AWS D1.2 structural welding protocols do not cover magnesium; shops typically work to AWS C3.7 or customer-supplied welding procedure specifications derived from MIL-STD-1595A. Finishing is where Meridian's environmental conditions matter most. Relative humidity in east-central Mississippi averages 70-75 percent through summer months, and magnesium's galvanic sensitivity makes bare surfaces vulnerable in humid storage. Conversion coating applied within four hours of final machining — followed by a primer coat rated for salt-fog resistance per ASTM B117 — is the practical standard. Shops that have invested in automated conversion-coat lines for aluminum anodizing can adapt those lines for magnesium with process parameter changes and chemistry swap-outs.

Meridian sits at the intersection of I-20 and I-59, two interstates that connect east-central Mississippi to Atlanta, Birmingham, Jackson, and the Gulf Coast ports. This highway network means magnesium sheet and billet ordered from domestic distributors in Chicago, Cleveland, or Houston typically arrives in two to three business days via LTL freight. For urgent defense program pulls, air freight into Meridian Regional Airport (MEI) is viable; the airport handles cargo and is approximately five miles from the city's industrial corridors. Magnesium sheet is typically shipped in wooden crates with moisture-barrier film and silica gel desiccant packs. Meridian buyers should specify "dry storage on arrival" and inspect packaging integrity before acceptance — moisture ingress during shipping in humid Gulf South weather can initiate surface oxidation that compromises coating adhesion. Stock stored on-site should be kept in climate-controlled warehousing at relative humidity below 50 percent. For high-volume programs, blanket purchase orders with quarterly releases from service center stock are the cost-effective approach. AZ31B sheet in standard mill sizes (48 by 144 inch, 0.063 to 0.250 inch) is stocked by national service centers; WE43 and specialized tempers may require mill order lead times of 8-16 weeks. ManufacturingBase connects Meridian buyers directly with vetted magnesium suppliers and regional job shops, compressing the sourcing cycle from weeks to days.