One of the first things a visitor observes upon entering the office of the chairman of American Security Corp. is a pair of desk plaques bearing the mottos: "Assume nothing" and "Make it happen."

The essence of those reminders to members of his management team at the corporation and its subsidiary, American Security Bank, was underscored by Chairman W. Jarvis Moody in a recent interview.

"You can't stay still in this business," the company's chief executive officer said. "You can't do it the same old way. You've got to be inventive and very much aware of risks."

That approach apparently has prompted the management of American Security to alter the thrust of its international operations.

Although that change began to emerge about two years ago, American Security has accelerated it to capitalize on increased interest by foreign companies in establishing firms in the United States.

In the past, American Security, like so many other nonmoney-center banks, developed a substantial part of its international business by participating in large loan syndications. That will continue, to some extent, but will give way to a more aggressive approach to building relationships with international customers, according to Moody.

"Rather than hanging everything on narrow-spread syndications, we have made a big thing of going after relationships, and particularly from the point of view of financing European organizations coming to the United States," Moody explained.

"I think one of the most important things banks are going to have to do in the future is not just be involved in lending money but, indeed, be involved in structuring deals that make sense for companies overseas."

Moody said that means explaining to foreign-based companies "why they should come here, and if they indeed do come here, how things should be structured. This is something that we have gotten into."

Beyond the profit to be made from a single deal, other considerations are important to a growth strategy, Moody noted.

"It's working out the tax angle, industrial revenue bond financing, putting together a package and having a relationship business as opposed to buying a sterile piece of somebody else's multibillion-dollar syndication," he said.

In that connection, Moody considers Europe "a great growth area" and believes it's important "to capitalize on those outfits that are coming here." His recent trip to Europe was designed to accomplish that by "solidifying relationships" with major industrial companies in Austria, Switzerland and Germany.

In the meantime, Moody just was elected to the board of Kloeckner Capital Corp. of America, a holding company that will be established in the United States by Kloeckner-Werke AG, an industrial giant based in Germany.

The new holding company's subsidiaries will include Kloeckner-Pentaplast of America Inc., a plastics manufacturing operation that opened two years ago in Gordonsville, Va., with revenue-bond financing handled by American Security.

One reason for Moody's European trip was to solidify the relationship with Kloeckner-Werke.

The Kloeckner-Pentaplast venture was the first of that type for American Security and "from that beginning came other" business, Moody said.

He cited the following spinoffs from that relationship:

* Emser Werke, a large producer of plastics and chemical products in Switzerland, has selected ASB as its "house" bank. "We will be the bank for what they do in the United States as they expand further," Moody said.

* Messer Griesheim, a German producer of industrial gases and welding equipment, with plants in Virginia and Pennsylvania, has established a banking relationship with ASB.

* Similar relationships have been established with Siemens AG of Germany, one of the world's largest producers of electrical products; Mercedes-Benz of North America; and Biederlach GMBH & Co. of Greven, Germany. The latter is a textile firm with a plant in Cumberland.

Meanwhile, American Security is negotiating a multimillion-dollar financing arrangement with a British manufacturer of trucks and heavy equipment. The firm has proposed building a plant in Prince George's County that would produce about 200 units by 1985.

At the same time, ASB is building relationships with prime banks around the world, including Deutsche Bank, Moody noted.

The new thrust that Moody outlined is in no way intended to tip the balance in favor of international banking at American Security, Moody emphasized.

"International has been and will continue to be 25 percent to 30 percent of our business," he said. "It's a balanced business, and the bank has a balanced portfolio."

Nonetheless, American Security has emerged as the pacesetter among regional banks in establishing new banking relationships with European firms that plan to establish, or already have established, U.S. subsidiaries.