01Flagship Line•Carbon
GRAPH-HEX® Recarburizers
Over 50 high-purity carbon additives engineered to individual customer specifications, with sulfur as low as 0.02%.
Specifications →
North American Leader · Since 1962
Forging theFutureof Steel.
Six decades of metallurgical mastery. We deliver high-performance carbon and graphite solutions to the world's most demanding foundries and steel mills.
5 Units
USA & China Bases
ISO 9001
Certified Quality
50+
GRAPH-HEX® SKUs
Global
Supply Network
North American Leader and World-Wide Supplier of Graphite and Carbon Additives Since 1962
Larpen Metallurgical Service is the industry expert in designing and adapting graphite and carbon additives for the foundry and steel industry. Established in 1962, we have been delivering unparalleled expertise in service, quality, consistency, and flexibility, ensuring our customers receive the highest quality products tailored to their individual needs.
Our Products Meet Your Needs
Product Excellence
Carbon engineered for performance.
Explore our extensive range of GRAPH-HEX products and other high quality graphite and carbon additives, each designed to meet the diverse needs of the foundry and steel industry. Our advanced processes and commitment to quality allow us to offer the most economical and reliable products in the market.
03 / Carbon engineered for performance.
01
02Steel & Iron•Carbon
Machined Graphite
Crystalline graphite for injection applications and EAF processes, with consistent purity and rapid dissolution.
Specifications →
03Foundry•Carbon
Pet Coke & Silicon Carbide
Low sulfur petroleum cokes (0.35–4.0% S) and Carbolon MA 90% silicon carbide for foundry chemistry.
Specifications →
Our Commitments
The benchmarks of an industry leader.
A family-run business operating with global scale — combining personal service with the rigor of ISO-certified quality systems and continuous improvement.
60+ Years
Family-run heritage since 1962.
ISO 9001
Certified quality management.
Own Laboratory
In-house testing & validation.
5 Plants
USA + China manufacturing.
Global Logistics
On-time delivery worldwide.
Unimetal Group
Backed by global expertise.
Operational Footprint
See all units & China hub →Strategic North American Presence
Interactive Map · USA + China
Our Evolution
Full timeline →Six decades of metallurgical milestones.
1962
Founding & Early Years
Henry Seeboth founds Larpen Supply Co, Inc, focused on Magna Flux and non-destructive testing equipment, then expands into foundry supply distribution.
1996
Expansion to Hartford
A new 50,000 sq. ft. manufacturing facility is built in Hartford, WI to meet North American demand.
2002
ISO Certification
Larpen achieves ISO 9001:2000 registration under the new QS 9000 Standard.
Today
Unimetal Group
Integrated into the Unimetal Group, combining family heritage with global technical expertise.
Let's Build Together
Ready to optimize your production?
Talk to our technical team about a custom carbon formulation engineered specifically for your foundry or steel mill.